Move the GL account mapping out of appsettings into validated master data

The per-module Gl*Code appsettings keys pinned GL's account *codes* in
ERPCore's config, while GL generates codes positionally and refuses a
requested one. Nothing connected the two, so "1100 means Inventory" held
only because someone once created accounts in a particular order - and on
2026-10-07 eleven of the twelve configured codes turned out never to have
existed in GL. Every GRN, adjustment, day-end, invoice and FIFO posting had
been failing with "Account <code> not found".

The mapping is now master data in gl_account_config, keyed by accounting
role rather than by module, and GlAccountConfigService validates every
submitted code against GL's live chart of accounts before storing it. A
code GL does not have, or cannot post to, is refused with the role named -
so the mismatch is unrepresentable rather than merely detected. Correcting
a mapping no longer needs a redeploy.

Notes:
- Fails closed on save (503 if GL is unreachable), deliberately opposite to
  the startup validator, which must still let the app serve.
- Non-postable accounts are rejected too: GL rejects a journal line against
  one, so storing it only defers the failure. The auto-created 1000
  Bank/Cash header is exactly that trap.
- The settings endpoint also serves the selectable accounts, because
  GeneralLedgerController is gated on `ledgers` while this is on `settings`
  - and it keeps the picker and the validation list the same data.
- Reading an unmapped role throws naming the role, instead of posting ""
  and letting GL return an opaque 404 from inside a transaction.
- The appsettings keys are now seed-only: DataSeeder copies them in once so
  existing deployments keep their current mapping. No runtime fallback, or
  there would be two sources of truth again.
- The 32 read sites across 11 services collapsed to 12 roles, since every
  module carried the same value for a given role.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Backend/ERPCore.Tests/GlAccountCodeValidatorTests.cs

@@ -1,8 +1,8 @@
 using ERPCore.Infra.Gl;
 using ERPCore.Services.Gl;
 using ERPCore.Services.Interfaces;
-using ERPCore.System.Errors;
 using ERPCore.System.Time;
+using ERPCore.Tests.TestSupport;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging.Abstractions;
@@ -10,37 +10,34 @@ using Microsoft.Extensions.Logging.Abstractions;
 namespace ERPCore.Tests;
 
 /// <summary>
-/// The validator's whole value is in *which* failures it treats as fatal: a missing account code
+/// The validator is advisory: enforcement lives in <see cref="ERPCore.Services.GlAccountConfigService"/>,
-/// must stop the app (the config is wrong), while an unreachable GL must not (GL shares the host
+/// which refuses to store a bad mapping in the first place. So the behaviour that matters here is that
-/// and may still be starting — hard-failing there turns that into a deploy crash-loop).
+/// it <b>cannot abort startup</b>. An earlier revision threw on a missing code and core-dumped
+/// erpcore.service on deploy (2026-10-07), turning a long-standing data mismatch into an outage.
 /// </summary>
 public class GlAccountCodeValidatorTests
 {
     [Fact]
-    public async Task StartAsync_Succeeds_WhenEveryConfiguredCodeExistsInGl()
+    public async Task StartAsync_Succeeds_WhenEveryMappedCodeExistsInGl()
     {
         var validator = CreateValidator(
-            new() { ["Grn:GlInventoryAccountCode"] = "1100", ["Fifo:GlClearingAccountCode"] = "2000" },
+            new(),
-            new StubGl(["1100", "2000", "4000"]));
+            new StubGeneralLedgerService([
+                StubGeneralLedgerService.Postable("1100"),
+                StubGeneralLedgerService.Postable("2000")
+            ]),
+            (GlAccountRole.Inventory, "1100"), (GlAccountRole.Clearing, "2000"));
 
         await validator.StartAsync(CancellationToken.None);
     }
 
-    /// <summary>
-    /// The default must not block startup. Throwing here cost an outage on 2026-10-07 — a config
-    /// mismatch that had existed all along became a core-dump the moment the check shipped.
-    /// </summary>
     [Fact]
-    public async Task StartAsync_DoesNotThrow_WhenCodesAreMissing_ByDefault()
+    public async Task StartAsync_DoesNotThrow_WhenMappedCodesAreMissingFromGl()
     {
         var validator = CreateValidator(
-            new()
+            new(),
-            {
+            new StubGeneralLedgerService([StubGeneralLedgerService.Postable("1000-01")]),
-                ["Grn:GlInventoryAccountCode"] = "1100",
+            (GlAccountRole.Inventory, "1100"), (GlAccountRole.Cash, "1000-01"));
-                ["SalesDayEnd:GlCashAccountCode"] = "1000-01",
-                ["Adjustment:GlLossAccountCode"] = "5100"
-            },
-            new StubGl(["1000-01"]));
 
         await validator.StartAsync(CancellationToken.None);
     }
@@ -49,14 +46,11 @@ public class GlAccountCodeValidatorTests
     public async Task StartAsync_Throws_AndNamesEveryMissingCode_WhenConfiguredToFail()
     {
         var validator = CreateValidator(
-            new()
+            new() { ["GeneralLedgerService:FailOnMissingAccountCodes"] = "true" },
-            {
+            new StubGeneralLedgerService([StubGeneralLedgerService.Postable("1100")]),
-                ["GeneralLedgerService:FailOnMissingAccountCodes"] = "true",
+            (GlAccountRole.Inventory, "1100"),
-                ["Grn:GlInventoryAccountCode"] = "1100",
+            (GlAccountRole.Cash, "1000-01"),
-                ["SalesDayEnd:GlCashAccountCode"] = "1000-01",
+            (GlAccountRole.InventoryLoss, "5100"));
-                ["Adjustment:GlLossAccountCode"] = "5100"
-            },
-            new StubGl(["1100"]));
 
         var ex = await Assert.ThrowsAsync<InvalidOperationException>(
             () => validator.StartAsync(CancellationToken.None));
@@ -64,97 +58,76 @@ public class GlAccountCodeValidatorTests
         Assert.Contains("1000-01", ex.Message);
         Assert.Contains("5100", ex.Message);
         Assert.Contains("2 of 3", ex.Message);
-        Assert.DoesNotContain("1100,", ex.Message);
     }
 
     /// <summary>
-    /// The deploy-killer: if GL's /accounts shape ever changes, the reader yields nothing and a naive
+    /// If GL's /accounts shape ever changes, the reader yields nothing. Treating that as
-    /// validator would call every configured code missing and refuse to start.
+    /// "everything is missing" would refuse to start on a contract change.
     /// </summary>
     [Fact]
-    public async Task StartAsync_DoesNotThrow_WhenGlReturnsNoCodesAtAll()
+    public async Task StartAsync_DoesNotThrow_WhenGlReturnsNoAccountsAtAll()
     {
         var validator = CreateValidator(
-            new() { ["Grn:GlInventoryAccountCode"] = "1100", ["Fifo:GlClearingAccountCode"] = "2000" },
+            new() { ["GeneralLedgerService:FailOnMissingAccountCodes"] = "true" },
-            new StubGl([]));
+            new StubGeneralLedgerService([]),
-
+            (GlAccountRole.Inventory, "1100"));
-        await validator.StartAsync(CancellationToken.None);
-    }
-
-    [Fact]
-    public async Task StartAsync_DoesNotThrow_WhenGlIsUnreachable()
-    {
-        var validator = CreateValidator(
-            new() { ["Grn:GlInventoryAccountCode"] = "1100" },
-            new StubGl(new DomainException(ErrorCodes.GlServiceUnavailable, "unreachable", 503)));
 
         await validator.StartAsync(CancellationToken.None);
     }
 
     /// <summary>
-    /// The earlier catch filter only matched DomainException/OperationCanceledException, so anything
+    /// The catch filter once matched only DomainException/OperationCanceledException, so anything
-    /// else — a parse failure, or a null `items` NRE in the reader — escaped and aborted the host.
+    /// else — a parse failure, a null-items NRE in the reader, a database hiccup reading the
-    /// A diagnostic must not be able to crash the thing it is diagnosing.
+    /// mapping — escaped a hosted service and aborted the host.
     /// </summary>
     [Theory]
     [MemberData(nameof(UnexpectedFailures))]
     public async Task StartAsync_DoesNotThrow_OnAnyUnexpectedFailure(Exception failure)
     {
         var validator = CreateValidator(
-            new() { ["Grn:GlInventoryAccountCode"] = "1100" },
+            new() { ["GeneralLedgerService:FailOnMissingAccountCodes"] = "true" },
-            new StubGl(failure));
+            new StubGeneralLedgerService(failure),
+            (GlAccountRole.Inventory, "1100"));
 
         await validator.StartAsync(CancellationToken.None);
     }
 
     public static TheoryData<Exception> UnexpectedFailures() =>
     [
+        StubGeneralLedgerService.Unreachable(),
         new NullReferenceException("items was null"),
         new global::System.Text.Json.JsonException("unexpected shape"),
         new InvalidOperationException("something else entirely"),
         new HttpRequestException("connection reset"),
+        new OperationCanceledException(),
     ];
 
     [Fact]
-    public async Task StartAsync_DoesNotThrow_WhenTheChartOfAccountsReadIsCancelled()
+    public async Task StartAsync_SkipsTheGlCall_WhenNothingIsMapped()
     {
-        var validator = CreateValidator(
+        var gl = new StubGeneralLedgerService([StubGeneralLedgerService.Postable("1100")]);
-            new() { ["Grn:GlInventoryAccountCode"] = "1100" },
-            new StubGl(new OperationCanceledException()));
 
-        await validator.StartAsync(CancellationToken.None);
-    }
-
-    /// <summary>Only `Gl*Code` keys are account codes — a sibling setting must not be demanded of GL.</summary>
-    [Fact]
-    public async Task StartAsync_IgnoresSettingsThatAreNotAccountCodes()
-    {
-        var gl = new StubGl(["1100"]);
-        var validator = CreateValidator(
-            new()
-            {
-                ["Grn:GlInventoryAccountCode"] = "1100",
-                ["Grn:GlPostingEnabled"] = "true",
-                ["Grn:SomeOtherCode"] = "not-an-account"
-            },
-            gl);
-
-        await validator.StartAsync(CancellationToken.None);
-
-        Assert.Equal(1, gl.Calls);
-    }
-
-    [Fact]
-    public async Task StartAsync_SkipsTheGlCall_WhenNoCodesAreConfigured()
-    {
-        var gl = new StubGl(["1100"]);
         var validator = CreateValidator(new(), gl);
-
         await validator.StartAsync(CancellationToken.None);
 
         Assert.Equal(0, gl.Calls);
     }
 
+    /// <summary>Duplicate codes across roles are one account to verify, not several.</summary>
+    [Fact]
+    public async Task StartAsync_DeduplicatesCodesSharedBySeveralRoles()
+    {
+        var gl = new StubGeneralLedgerService([StubGeneralLedgerService.Postable("1100")]);
+
+        var validator = CreateValidator(
+            new() { ["GeneralLedgerService:FailOnMissingAccountCodes"] = "true" },
+            gl,
+            (GlAccountRole.Inventory, "1100"), (GlAccountRole.InventoryGain, "1100"));
+
+        await validator.StartAsync(CancellationToken.None);
+        Assert.Equal(1, gl.Calls);
+    }
+
     /// <summary>Asia/Colombo is UTC+05:30, so 20:00 UTC on the 31st is already the 1st locally.</summary>
     [Fact]
     public void BusinessClock_MapsAUtcInstantToTheLocalBusinessDay()
@@ -165,39 +138,14 @@ public class GlAccountCodeValidatorTests
         Assert.Equal(new DateOnly(2026, 11, 1), BusinessClock.ToBusinessDate(new DateTime(2026, 10, 31, 18, 30, 0, DateTimeKind.Utc)));
     }
 
-    private static GlAccountCodeValidator CreateValidator(Dictionary<string, string?> settings, IGeneralLedgerService gl)
+    private static GlAccountCodeValidator CreateValidator(
+        Dictionary<string, string?> settings, StubGeneralLedgerService gl, params (GlAccountRole, string?)[] mapping)
     {
         var configuration = new ConfigurationBuilder().AddInMemoryCollection(settings).Build();
-        var services = new ServiceCollection().AddScoped(_ => gl).BuildServiceProvider();
+        var services = new ServiceCollection()
+            .AddScoped<IGeneralLedgerService>(_ => gl)
+            .AddScoped<IGlAccountConfigService>(_ => new StubGlAccountConfigService(mapping))
+            .BuildServiceProvider();
         return new GlAccountCodeValidator(services, configuration, NullLogger<GlAccountCodeValidator>.Instance);
     }
-
-    private sealed class StubGl(HashSet<string>? codes = null, Exception? throws = null) : IGeneralLedgerService
-    {
-        private readonly HashSet<string> _codes = codes ?? [];
-        private readonly Exception? _throws = throws;
-
-        public StubGl(Exception throws) : this(null, throws) { }
-
-        public int Calls { get; private set; }
-
-        public Task<HashSet<string>> ListAccountCodesAsync(CancellationToken ct)
-        {
-            Calls++;
-            return _throws is not null ? Task.FromException<HashSet<string>>(_throws) : Task.FromResult(_codes);
-        }
-
-        public Task<ERPCore.Infra.Gl.GeneralLedgerResponse> ForwardAsync(
-            HttpMethod method, string path, string? queryString, string? contentType, Stream? body, CancellationToken ct)
-            => throw new NotSupportedException();
-
-        public Task<GlJournalEntryResult> PostJournalEntryAsync(GlJournalEntryRequest request, CancellationToken ct)
-            => throw new NotSupportedException();
-
-        public Task<GlPeriod> GetPeriodByDateAsync(DateOnly date, CancellationToken ct)
-            => throw new NotSupportedException();
-
-        public Task<IReadOnlyList<GlBankAccount>> ListBankAccountsAsync(CancellationToken ct)
-            => throw new NotSupportedException();
-    }
 }

Backend/ERPCore.Tests/GlAccountConfigServiceTests.cs

@@ -0,0 +1,234 @@
+using ERPCore.Domain.Entities;
+using ERPCore.Dtos.Config;
+using ERPCore.Infra.Persistence;
+using ERPCore.Repositories;
+using ERPCore.Services;
+using ERPCore.Services.Gl;
+using ERPCore.Services.Interfaces;
+using ERPCore.System.Errors;
+using ERPCore.Tests.TestSupport;
+
+namespace ERPCore.Tests;
+
+/// <summary>
+/// The point of this service is that a mapping GL cannot post to never reaches the database.
+/// Validation at the point of entry is what the old appsettings approach could not do: those codes
+/// were only ever checked at boot, and on 2026-10-07 eleven of twelve turned out never to have
+/// existed in GL at all.
+/// </summary>
+public class GlAccountConfigServiceTests
+{
+    [Fact]
+    public async Task UpdateAsync_PersistsAMappingGlCanPostTo()
+    {
+        await using var db = await CreateSeededContextAsync();
+        var gl = new StubGeneralLedgerService([
+            StubGeneralLedgerService.Postable("1100", "Inventory"),
+            StubGeneralLedgerService.Postable("2000", "GRNI")
+        ]);
+        var service = CreateService(db, gl);
+        var before = (await service.GetAsync()).RowVersion;
+
+        var result = await service.UpdateAsync(
+            new UpdateGlAccountConfigRequest { InventoryAccountCode = "1100", ClearingAccountCode = "2000" }, before);
+
+        Assert.True(result.RowVersion > before);
+        var codes = await CreateService(db, gl).GetCodesAsync();
+        Assert.Equal("1100", codes[GlAccountRole.Inventory]);
+        Assert.Equal("2000", codes[GlAccountRole.Clearing]);
+    }
+
+    [Fact]
+    public async Task UpdateAsync_RejectsACodeGlDoesNotHave_AndNamesIt()
+    {
+        await using var db = await CreateSeededContextAsync();
+        var service = CreateService(db, new StubGeneralLedgerService([StubGeneralLedgerService.Postable("1100")]));
+        var rowVersion = (await service.GetAsync()).RowVersion;
+
+        var ex = await Assert.ThrowsAsync<DomainException>(() => service.UpdateAsync(
+            new UpdateGlAccountConfigRequest { InventoryAccountCode = "1100", ClearingAccountCode = "9999" }, rowVersion));
+
+        Assert.Equal(ErrorCodes.GlAccountInvalid, ex.Code);
+        Assert.Equal(422, ex.StatusCode);
+        Assert.Contains("9999", ex.Message);
+        Assert.Contains("Clearing", ex.Message);
+        await AssertNothingStoredAsync(db);
+    }
+
+    /// <summary>
+    /// GL rejects a journal line against a non-postable account, so storing one only defers the
+    /// failure to posting time. The auto-created <c>1000</c> Bank/Cash header is exactly this trap.
+    /// </summary>
+    [Fact]
+    public async Task UpdateAsync_RejectsANonPostableAccount()
+    {
+        await using var db = await CreateSeededContextAsync();
+        var service = CreateService(db, new StubGeneralLedgerService([
+            StubGeneralLedgerService.NotPostable("1000", "Bank and Cash")
+        ]));
+        var rowVersion = (await service.GetAsync()).RowVersion;
+
+        var ex = await Assert.ThrowsAsync<DomainException>(() => service.UpdateAsync(
+            new UpdateGlAccountConfigRequest { CashAccountCode = "1000" }, rowVersion));
+
+        Assert.Equal(ErrorCodes.GlAccountInvalid, ex.Code);
+        Assert.Contains("not postable", ex.Message);
+        await AssertNothingStoredAsync(db);
+    }
+
+    /// <summary>Fails closed, deliberately opposite to the startup validator: an unverified mapping is not a valid one.</summary>
+    [Fact]
+    public async Task UpdateAsync_RefusesToSaveWhenGlIsUnreachable()
+    {
+        await using var db = await CreateSeededContextAsync();
+        var service = CreateService(db, new StubGeneralLedgerService(StubGeneralLedgerService.Unreachable()));
+
+        var ex = await Assert.ThrowsAsync<DomainException>(() => service.UpdateAsync(
+            new UpdateGlAccountConfigRequest { InventoryAccountCode = "1100" }, 1));
+
+        Assert.Equal(ErrorCodes.GlServiceUnavailable, ex.Code);
+        await AssertNothingStoredAsync(db);
+    }
+
+    [Fact]
+    public async Task UpdateAsync_RefusesToSaveAgainstAnEmptyChartOfAccounts()
+    {
+        await using var db = await CreateSeededContextAsync();
+        var service = CreateService(db, new StubGeneralLedgerService([]));
+        var rowVersion = (await service.GetAsync()).RowVersion;
+
+        var ex = await Assert.ThrowsAsync<DomainException>(() => service.UpdateAsync(
+            new UpdateGlAccountConfigRequest { InventoryAccountCode = "1100" }, rowVersion));
+
+        Assert.Equal(ErrorCodes.GlAccountInvalid, ex.Code);
+        Assert.Equal(503, ex.StatusCode);
+    }
+
+    [Fact]
+    public async Task UpdateAsync_RejectsAStaleIfMatch()
+    {
+        await using var db = await CreateSeededContextAsync();
+        var service = CreateService(db, new StubGeneralLedgerService([StubGeneralLedgerService.Postable("1100")]));
+
+        var ex = await Assert.ThrowsAsync<DomainException>(() => service.UpdateAsync(
+            new UpdateGlAccountConfigRequest { InventoryAccountCode = "1100" }, expectedRowVersion: 9999));
+
+        Assert.Equal(ErrorCodes.ConcurrencyConflict, ex.Code);
+        Assert.Equal(412, ex.StatusCode);
+    }
+
+    /// <summary>An empty string clears a role rather than storing "" and posting it to GL.</summary>
+    [Fact]
+    public async Task UpdateAsync_TreatsBlankAsCleared()
+    {
+        await using var db = await CreateSeededContextAsync();
+        var gl = new StubGeneralLedgerService([StubGeneralLedgerService.Postable("1100")]);
+        var service = CreateService(db, gl);
+        var rowVersion = (await service.GetAsync()).RowVersion;
+
+        await service.UpdateAsync(new UpdateGlAccountConfigRequest { InventoryAccountCode = "   " }, rowVersion);
+
+        var codes = await CreateService(db, gl).GetCodesAsync();
+        Assert.Null(codes.GetOrNull(GlAccountRole.Inventory));
+    }
+
+    /// <summary>Reading an unmapped role names the role, instead of posting "" and letting GL 404.</summary>
+    [Fact]
+    public async Task GetCodesAsync_ThrowsNamingTheRole_WhenUnmapped()
+    {
+        await using var db = await CreateSeededContextAsync();
+        var service = CreateService(db, new StubGeneralLedgerService([]));
+
+        var codes = await service.GetCodesAsync();
+        var ex = Assert.Throws<DomainException>(() => codes[GlAccountRole.Cogs]);
+
+        Assert.Equal(ErrorCodes.GlAccountNotConfigured, ex.Code);
+        Assert.Contains("Cogs", ex.Message);
+    }
+
+    /// <summary>One request can post through several services; they should not each re-read the row.</summary>
+    [Fact]
+    public async Task GetCodesAsync_ReadsOncePerScope()
+    {
+        await using var db = await CreateSeededContextAsync();
+        var service = CreateService(db, new StubGeneralLedgerService([]));
+
+        var first = await service.GetCodesAsync();
+        var second = await service.GetCodesAsync();
+
+        Assert.Same(first, second);
+    }
+
+    /// <summary>GL being down must not stop the saved mapping from rendering on the settings screen.</summary>
+    [Fact]
+    public async Task GetAsync_StillReturnsTheMapping_WhenGlIsUnreachable()
+    {
+        await using var db = await CreateSeededContextAsync(c => c.InventoryAccountCode = "1100");
+        var service = CreateService(db, new StubGeneralLedgerService(StubGeneralLedgerService.Unreachable()));
+
+        var result = await service.GetAsync();
+
+        Assert.True(result.Value.GlUnavailable);
+        Assert.Empty(result.Value.Options);
+        var inventory = result.Value.Mappings.Single(m => m.Role == nameof(GlAccountRole.Inventory));
+        Assert.Equal("1100", inventory.AccountCode);
+    }
+
+    /// <summary>The 2026-10-07 state: a stored code GL does not have is shown flagged, not blank.</summary>
+    [Fact]
+    public async Task GetAsync_FlagsAStoredCodeThatGlDoesNotHave()
+    {
+        await using var db = await CreateSeededContextAsync(c =>
+        {
+            c.InventoryAccountCode = "1100";
+            c.CashAccountCode = "1000-01";
+        });
+        var service = CreateService(db, new StubGeneralLedgerService([
+            StubGeneralLedgerService.Postable("1000-01", "Cash in Hand")
+        ]));
+
+        var result = await service.GetAsync();
+
+        Assert.False(result.Value.Mappings.Single(m => m.Role == nameof(GlAccountRole.Inventory)).ExistsInGl);
+        Assert.True(result.Value.Mappings.Single(m => m.Role == nameof(GlAccountRole.Cash)).ExistsInGl);
+    }
+
+    /// <summary>The picker must only offer what validation will accept.</summary>
+    [Fact]
+    public async Task GetAsync_OffersOnlyPostableActiveAccounts()
+    {
+        await using var db = await CreateSeededContextAsync();
+        var service = CreateService(db, new StubGeneralLedgerService([
+            StubGeneralLedgerService.Postable("1100", "Inventory"),
+            StubGeneralLedgerService.NotPostable("1000", "Bank and Cash"),
+            new GlAccount("1200", "Retired", 1, true, false)
+        ]));
+
+        var options = (await service.GetAsync()).Value.Options;
+
+        Assert.Equal(["1100"], options.Select(o => o.AccountCode));
+    }
+
+    private static async Task AssertNothingStoredAsync(ErpDbContext db)
+    {
+        var row = await new Repository<GlAccountConfig>(db).GetByIdAsync(GlAccountConfig.SingletonId);
+        Assert.Null(row!.InventoryAccountCode);
+        Assert.Null(row.ClearingAccountCode);
+        Assert.Null(row.CashAccountCode);
+    }
+
+    private static async Task<ErpDbContext> CreateSeededContextAsync(Action<GlAccountConfig>? configure = null)
+    {
+        var db = NotificationConfigTestSupport.CreateContext(Guid.NewGuid().ToString("N"));
+        db.Users.Add(new User { UserId = User.SystemUserId, Username = "system", DisplayName = "System" });
+
+        var config = new GlAccountConfig { ConfigId = GlAccountConfig.SingletonId };
+        configure?.Invoke(config);
+        db.GlAccountConfig.Add(config);
+        await db.SaveChangesAsync();
+        return db;
+    }
+
+    private static GlAccountConfigService CreateService(ErpDbContext db, IGeneralLedgerService gl) =>
+        new(new Repository<GlAccountConfig>(db), gl, new TestCurrentUser(), new ERPCore.Infra.UoW.UnitOfWork(db));
+}

Backend/ERPCore.Tests/TestSupport/GlTestSupport.cs

@@ -0,0 +1,66 @@
+using ERPCore.Infra.Gl;
+using ERPCore.Services.Gl;
+using ERPCore.Services.Interfaces;
+using ERPCore.System.Errors;
+
+namespace ERPCore.Tests.TestSupport;
+
+/// <summary>
+/// Stands in for the external GL service. Only <see cref="ListAccountsAsync"/> is implemented —
+/// nothing under test here posts a journal, and leaving the rest throwing means a test that starts
+/// doing so fails loudly rather than against a silently empty fake.
+/// </summary>
+internal sealed class StubGeneralLedgerService : IGeneralLedgerService
+{
+    private readonly IReadOnlyList<GlAccount> _accounts;
+    private readonly Exception? _throws;
+
+    public StubGeneralLedgerService(IReadOnlyList<GlAccount> accounts) => _accounts = accounts;
+    public StubGeneralLedgerService(Exception throws) { _accounts = []; _throws = throws; }
+
+    public int Calls { get; private set; }
+
+    /// <summary>A postable, active account — the ordinary case.</summary>
+    public static GlAccount Postable(string code, string name = "Account", short type = 1) => new(code, name, type, true, true);
+
+    /// <summary>A header/control account. GL rejects journal lines against these.</summary>
+    public static GlAccount NotPostable(string code, string name = "Header", short type = 1) => new(code, name, type, false, true);
+
+    public Task<IReadOnlyList<GlAccount>> ListAccountsAsync(CancellationToken ct)
+    {
+        Calls++;
+        return _throws is not null
+            ? Task.FromException<IReadOnlyList<GlAccount>>(_throws)
+            : Task.FromResult(_accounts);
+    }
+
+    public Task<GeneralLedgerResponse> ForwardAsync(
+        HttpMethod method, string path, string? queryString, string? contentType, Stream? body, CancellationToken ct)
+        => throw new NotSupportedException();
+
+    public Task<GlJournalEntryResult> PostJournalEntryAsync(GlJournalEntryRequest request, CancellationToken ct)
+        => throw new NotSupportedException();
+
+    public Task<GlPeriod> GetPeriodByDateAsync(DateOnly date, CancellationToken ct)
+        => throw new NotSupportedException();
+
+    public Task<IReadOnlyList<GlBankAccount>> ListBankAccountsAsync(CancellationToken ct)
+        => throw new NotSupportedException();
+
+    public static DomainException Unreachable() =>
+        new(ErrorCodes.GlServiceUnavailable, "The General Ledger service is unreachable.", 503);
+}
+
+/// <summary>Returns a fixed mapping, for exercising the startup validator without a database.</summary>
+internal sealed class StubGlAccountConfigService(params (GlAccountRole Role, string? Code)[] mappings) : IGlAccountConfigService
+{
+    public Task<GlAccountCodes> GetCodesAsync(CancellationToken ct = default) =>
+        Task.FromResult(new GlAccountCodes(mappings.ToDictionary(m => m.Role, m => m.Code)));
+
+    public Task<ERPCore.Common.Http.ETagged<ERPCore.Dtos.Config.GlAccountConfigDto>> GetAsync(CancellationToken ct = default)
+        => throw new NotSupportedException();
+
+    public Task<ERPCore.Common.Http.ETagged<ERPCore.Dtos.Config.GlAccountConfigDto>> UpdateAsync(
+        ERPCore.Dtos.Config.UpdateGlAccountConfigRequest request, uint expectedRowVersion, CancellationToken ct = default)
+        => throw new NotSupportedException();
+}

Backend/ERPCore/Controllers/GlAccountConfigController.cs

@@ -0,0 +1,53 @@
+using ERPCore.Dtos.Config;
+using ERPCore.Infra.Auth;
+using ERPCore.Services.Interfaces;
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+
+namespace ERPCore.Controllers;
+
+/// <summary>
+/// Role → GL account mapping endpoints.
+/// <para>
+/// <b>Authorization:</b> the <c>settings</c> nav policy, like <see cref="BranchConfigController"/>.
+/// Note this endpoint also serves the selectable accounts, rather than the screen calling the GL
+/// proxy directly: <see cref="GeneralLedgerController"/> is gated on <c>ledgers</c>, so a
+/// settings-only user would get a 403 from it — and serving both from here guarantees the picker
+/// and the server-side validation work from the same list.
+/// </para>
+/// </summary>
+[Route("api/v1/gl-account-config")]
+[Authorize(Policy = NavPolicies.Prefix + "settings")]
+public sealed class GlAccountConfigController : ApiControllerBase
+{
+    private readonly IGlAccountConfigService _config;
+
+    public GlAccountConfigController(IGlAccountConfigService config) => _config = config;
+
+    [HttpGet]
+    [ProducesResponseType(typeof(GlAccountConfigDto), StatusCodes.Status200OK)]
+    public async Task<ActionResult<GlAccountConfigDto>> Get(CancellationToken ct)
+    {
+        var result = await _config.GetAsync(ct);
+        SetETag(result.RowVersion);
+        return Ok(result.Value);
+    }
+
+    /// <summary>
+    /// Replaces the mapping. 422 when a code is unknown to GL or not postable; 503 when GL could
+    /// not be reached, since a mapping that could not be verified is not stored.
+    /// </summary>
+    [HttpPut]
+    [ProducesResponseType(typeof(GlAccountConfigDto), StatusCodes.Status200OK)]
+    [ProducesResponseType(StatusCodes.Status412PreconditionFailed)]
+    [ProducesResponseType(StatusCodes.Status422UnprocessableEntity)]
+    [ProducesResponseType(StatusCodes.Status503ServiceUnavailable)]
+    public async Task<ActionResult<GlAccountConfigDto>> Update(
+        [FromBody] UpdateGlAccountConfigRequest request, CancellationToken ct)
+    {
+        var expected = RequireIfMatch();
+        var result = await _config.UpdateAsync(request, expected, ct);
+        SetETag(result.RowVersion);
+        return Ok(result.Value);
+    }
+}

Backend/ERPCore/Dtos/Config/GlAccountConfigDtos.cs

@@ -0,0 +1,50 @@
+using System.ComponentModel.DataAnnotations;
+using ERPCore.Domain.Entities;
+
+namespace ERPCore.Dtos.Config;
+
+/// <summary>One selectable GL account, for the mapping pickers.</summary>
+public sealed record GlAccountOptionDto(string AccountCode, string AccountName, short AccountTypeId, bool IsPostable, bool IsActive);
+
+/// <summary>
+/// One role's current mapping. <see cref="ExistsInGl"/> is false when the saved code is not in GL's
+/// chart of accounts — which is the state 11 of these were found in on 2026-10-07. The screen shows
+/// those as flagged rather than blank, so the mapping that is actually stored stays visible.
+/// </summary>
+public sealed record GlAccountMappingDto(
+    string Role, string? AccountCode, string? AccountName, bool ExistsInGl, bool IsPostable);
+
+/// <summary>
+/// GL account mapping resource. Carries the options alongside the mappings so the picker and the
+/// server's validation list are the same data — a code the user can choose is a code that will save.
+/// <para>
+/// <see cref="GlUnavailable"/> is true when GL could not be reached: mappings still render from the
+/// database, <see cref="Options"/> is empty, and saving will be refused until GL answers.
+/// </para>
+/// </summary>
+public sealed record GlAccountConfigDto(
+    IReadOnlyList<GlAccountMappingDto> Mappings,
+    IReadOnlyList<GlAccountOptionDto> Options,
+    bool GlUnavailable,
+    DateTime? UpdatedAt,
+    int? UpdatedBy);
+
+/// <summary>
+/// Full replacement of the mapping. Every role is sent on every save; null or empty clears a role.
+/// <c>UpdatedBy</c> is derived from the token, never posted.
+/// </summary>
+public sealed class UpdateGlAccountConfigRequest
+{
+    [MaxLength(GlAccountConfig.CodeMaxLength)] public string? InventoryAccountCode { get; set; }
+    [MaxLength(GlAccountConfig.CodeMaxLength)] public string? VatRecoverableAccountCode { get; set; }
+    [MaxLength(GlAccountConfig.CodeMaxLength)] public string? AccountsReceivableCode { get; set; }
+    [MaxLength(GlAccountConfig.CodeMaxLength)] public string? ClearingAccountCode { get; set; }
+    [MaxLength(GlAccountConfig.CodeMaxLength)] public string? TaxPayableAccountCode { get; set; }
+    [MaxLength(GlAccountConfig.CodeMaxLength)] public string? AccountsPayableCode { get; set; }
+    [MaxLength(GlAccountConfig.CodeMaxLength)] public string? SalesRevenueAccountCode { get; set; }
+    [MaxLength(GlAccountConfig.CodeMaxLength)] public string? SalesDiscountAccountCode { get; set; }
+    [MaxLength(GlAccountConfig.CodeMaxLength)] public string? InventoryGainAccountCode { get; set; }
+    [MaxLength(GlAccountConfig.CodeMaxLength)] public string? CogsAccountCode { get; set; }
+    [MaxLength(GlAccountConfig.CodeMaxLength)] public string? InventoryLossAccountCode { get; set; }
+    [MaxLength(GlAccountConfig.CodeMaxLength)] public string? CashAccountCode { get; set; }
+}

Backend/ERPCore/Infra/Gl/GlAccountCodeValidator.cs

@@ -1,12 +1,18 @@
+using ERPCore.Services.Gl;
 using ERPCore.Services.Interfaces;
 
 namespace ERPCore.Infra.Gl;
 
 /// <summary>
-/// Startup guard for the GL chart of accounts. Every <c>Gl*Code</c> in configuration names an
+/// Startup guard for the GL chart of accounts. Every account mapped in <c>gl_account_config</c>
-/// account that must already exist in GL; until now a typo or an un-seeded account only surfaced
+/// must exist in GL; without this, an un-seeded account only surfaced as a 404 when some user
-/// as a 404 when some user happened to trigger that one flow, mid-transaction — one flow, one
+/// happened to trigger that one flow, mid-transaction — one flow, one discovery, repeat. This
-/// discovery, repeat. This asserts the whole set once, at boot.
+/// asserts the whole set once, at boot.
+/// <para>
+/// Advisory only. Enforcement lives at the point of entry — <c>GlAccountConfigService.UpdateAsync</c>
+/// refuses to store a code GL does not have or cannot post to — so this is a net for accounts that
+/// disappeared from GL *after* being mapped.
+/// </para>
 /// <para>
 /// <b>Reports, does not block.</b> An earlier revision threw on a missing code, on the reasoning
 /// that the config is wrong and waiting won't fix it. In practice that took erpcore.service down
@@ -26,39 +32,41 @@ public sealed class GlAccountCodeValidator(
     IConfiguration configuration,
     ILogger<GlAccountCodeValidator> logger) : IHostedService
 {
-    /// <summary>Configuration sections that carry GL account codes — see appsettings.json.</summary>
-    private static readonly string[] Sections =
-        ["Grn", "SalesDayEnd", "Adjustment", "SalesInvoice", "PurchaseInvoice", "Fifo"];
-
     /// <summary>Startup must not stall on a hung GL — HttpClient's own default is 100s.</summary>
     private static readonly TimeSpan FetchTimeout = TimeSpan.FromSeconds(10);
 
     public async Task StartAsync(CancellationToken ct)
     {
-        var expected = Sections
+        string[] expected;
-            .SelectMany(s => configuration.GetSection(s).GetChildren())
+        HashSet<string> present;
-            .Where(c => c.Key.StartsWith("Gl", StringComparison.Ordinal) && c.Key.EndsWith("Code", StringComparison.Ordinal))
+
-            .Select(c => c.Value)
+        // The database read sits inside the catch-all too: a DB hiccup here would otherwise escape
-            .Where(v => !string.IsNullOrWhiteSpace(v))
+        // a hosted service and reopen the startup-abort hole this class already caused once.
-            .Select(v => v!)
+        try
+        {
+            using var scope = services.CreateScope();
+            var mapping = scope.ServiceProvider.GetRequiredService<IGlAccountConfigService>();
+            var gl = scope.ServiceProvider.GetRequiredService<IGeneralLedgerService>();
+
+            var codes = await mapping.GetCodesAsync(ct);
+            expected = Enum.GetValues<GlAccountRole>()
+                .Select(codes.GetOrNull)
+                .Where(c => c is not null)
+                .Select(c => c!)
                 .Distinct(StringComparer.Ordinal)
                 .ToArray();
 
             if (expected.Length == 0)
             {
-            logger.LogWarning("No GL account codes are configured — skipping chart-of-accounts verification.");
+                logger.LogWarning(
+                    "No GL accounts are mapped — skipping chart-of-accounts verification. "
+                    + "Map them under Settings → GL Accounts; posting flows will fail until then.");
                 return;
             }
 
-        HashSet<string> present;
-        try
-        {
-            using var scope = services.CreateScope();
-            var gl = scope.ServiceProvider.GetRequiredService<IGeneralLedgerService>();
-
             using var timeout = CancellationTokenSource.CreateLinkedTokenSource(ct);
             timeout.CancelAfter(FetchTimeout);
-            present = await gl.ListAccountCodesAsync(timeout.Token);
+            present = (await gl.ListAccountsAsync(timeout.Token)).Select(a => a.AccountCode).ToHashSet(StringComparer.Ordinal);
         }
         // Catch-all on purpose. This is a diagnostic, and a diagnostic that can abort the host is
         // worse than no diagnostic — whatever GL answers with (unreachable, a timeout, a redirect,
@@ -67,8 +75,7 @@ public sealed class GlAccountCodeValidator(
         catch (Exception e) when (!ct.IsCancellationRequested)
         {
             logger.LogWarning(e,
-                "Could not read GL's chart of accounts at startup; {Count} configured account code(s) left unverified.",
+                "Could not verify the GL account mapping at startup; it is left unchecked.");
-                expected.Length);
             return;
         }
 
@@ -78,7 +85,7 @@ public sealed class GlAccountCodeValidator(
         if (present.Count == 0)
         {
             logger.LogWarning(
-                "GL returned no account codes; {Count} configured account code(s) left unverified. " +
+                "GL returned no account codes; {Count} mapped account code(s) left unverified. " +
                 "If GL's chart of accounts is not actually empty, the /accounts response shape has changed.",
                 expected.Length);
             return;
@@ -88,10 +95,10 @@ public sealed class GlAccountCodeValidator(
         if (missing.Length > 0)
         {
             var message =
-                $"General Ledger is missing {missing.Length} of {expected.Length} configured account code(s): " +
+                $"General Ledger is missing {missing.Length} of {expected.Length} mapped account code(s): " +
                 $"{string.Join(", ", missing.Order(StringComparer.Ordinal))}. Every flow that posts to one of these " +
-                "will fail against GL until they are seeded in GL's chart of accounts, or the Gl*Code settings are " +
+                "will fail against GL until the accounts are created in GL, or the mapping is corrected under " +
-                "corrected to match the codes GL actually uses.";
+                "Settings → GL Accounts.";
 
             if (configuration.GetValue("GeneralLedgerService:FailOnMissingAccountCodes", false))
                 throw new InvalidOperationException(message);
@@ -100,7 +107,7 @@ public sealed class GlAccountCodeValidator(
             return;
         }
 
-        logger.LogInformation("GL account codes verified: {Count} present.", expected.Length);
+        logger.LogInformation("GL account mapping verified: {Count} account code(s) present.", expected.Length);
     }
 
     public Task StopAsync(CancellationToken ct) => Task.CompletedTask;

Backend/ERPCore/Infra/Persistence/DataSeeder.cs

@@ -47,7 +47,8 @@ public static class DataSeeder
         ("PRD-REWORK-LOSS", "Production Rework Loss", ReasonContext.Production),
     ];
 
-    public static async Task SeedAsync(ErpDbContext db, CancellationToken ct = default)
+    public static async Task SeedAsync(
+        ErpDbContext db, IConfiguration? configuration = null, CancellationToken ct = default)
     {
         // Must come first, and must save on its own: every branch-scoped entity has a
         // non-nullable BranchId with a Restrict FK, so nothing branch-scoped can be written
@@ -60,6 +61,7 @@ public static class DataSeeder
         dirty |= await SeedBranchConfigAsync(db, ct);
         dirty |= await SeedSalesConfigAsync(db, ct);
         dirty |= await SeedGrnConfigAsync(db, ct);
+        dirty |= await SeedGlAccountConfigAsync(db, configuration, ct);
         dirty |= await SeedNotificationConfigAsync(db, ct);
 
         if (dirty) await db.SaveChangesAsync(ct);
@@ -199,6 +201,49 @@ public static class DataSeeder
         return true;
     }
 
+    /// <summary>
+    /// Seeds the GL account mapping singleton, carrying over the legacy <c>Gl*Code</c> appsettings
+    /// values once so an existing deployment keeps the mapping it has been running with.
+    /// <para>
+    /// Those keys are <b>seed-only</b>: nothing reads them at runtime any more. Leaving a runtime
+    /// fallback in place would restore the two-sources-of-truth problem this table exists to end —
+    /// after seeding, <c>gl_account_config</c> is authoritative and is edited from
+    /// Settings → GL Accounts, not by redeploying.
+    /// </para>
+    /// <para>
+    /// Deliberately does not call GL: seeding runs inside the startup block that aborts the app on
+    /// failure (see Program.cs), so it must not depend on another service being up. The codes are
+    /// verified separately — advisory at boot by <c>GlAccountCodeValidator</c>, and enforced on
+    /// every save by <c>GlAccountConfigService.UpdateAsync</c>.
+    /// </para>
+    /// </summary>
+    private static async Task<bool> SeedGlAccountConfigAsync(
+        ErpDbContext db, IConfiguration? configuration, CancellationToken ct)
+    {
+        if (await db.GlAccountConfig.AnyAsync(c => c.ConfigId == GlAccountConfig.SingletonId, ct)) return false;
+
+        string? Legacy(string key) =>
+            string.IsNullOrWhiteSpace(configuration?[key]) ? null : configuration[key]!.Trim();
+
+        db.GlAccountConfig.Add(new GlAccountConfig
+        {
+            ConfigId = GlAccountConfig.SingletonId,
+            InventoryAccountCode = Legacy("Grn:GlInventoryAccountCode"),
+            VatRecoverableAccountCode = Legacy("Grn:GlVatRecoverableAccountCode"),
+            AccountsReceivableCode = Legacy("SalesInvoice:GlAccountsReceivableCode"),
+            ClearingAccountCode = Legacy("Grn:GlClearingAccountCode"),
+            TaxPayableAccountCode = Legacy("SalesDayEnd:GlTaxPayableAccountCode"),
+            AccountsPayableCode = Legacy("PurchaseInvoice:GlAccountsPayableCode"),
+            SalesRevenueAccountCode = Legacy("SalesDayEnd:GlSalesRevenueAccountCode"),
+            SalesDiscountAccountCode = Legacy("SalesDayEnd:GlSalesDiscountAccountCode"),
+            InventoryGainAccountCode = Legacy("Adjustment:GlGainAccountCode"),
+            CogsAccountCode = Legacy("SalesDayEnd:GlCogsAccountCode"),
+            InventoryLossAccountCode = Legacy("Adjustment:GlLossAccountCode"),
+            CashAccountCode = Legacy("SalesDayEnd:GlCashAccountCode")
+        });
+        return true;
+    }
+
     private static async Task<bool> SeedNotificationConfigAsync(ErpDbContext db, CancellationToken ct)
     {
         if (await db.NotificationConfig.AnyAsync(c => c.NotificationConfigId == NotificationConfig.SingletonId, ct)) return false;

Backend/ERPCore/Migrations/20261007072921_AddGlAccountConfig.cs

@@ -0,0 +1,61 @@
+using System;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace ERPCore.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddGlAccountConfig : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.CreateTable(
+                name: "gl_account_config",
+                columns: table => new
+                {
+                    ConfigId = table.Column<int>(type: "int", nullable: false),
+                    InventoryAccountCode = table.Column<string>(type: "varchar(20)", maxLength: 20, nullable: true, collation: "utf8mb4_unicode_ci"),
+                    VatRecoverableAccountCode = table.Column<string>(type: "varchar(20)", maxLength: 20, nullable: true, collation: "utf8mb4_unicode_ci"),
+                    AccountsReceivableCode = table.Column<string>(type: "varchar(20)", maxLength: 20, nullable: true, collation: "utf8mb4_unicode_ci"),
+                    ClearingAccountCode = table.Column<string>(type: "varchar(20)", maxLength: 20, nullable: true, collation: "utf8mb4_unicode_ci"),
+                    TaxPayableAccountCode = table.Column<string>(type: "varchar(20)", maxLength: 20, nullable: true, collation: "utf8mb4_unicode_ci"),
+                    AccountsPayableCode = table.Column<string>(type: "varchar(20)", maxLength: 20, nullable: true, collation: "utf8mb4_unicode_ci"),
+                    SalesRevenueAccountCode = table.Column<string>(type: "varchar(20)", maxLength: 20, nullable: true, collation: "utf8mb4_unicode_ci"),
+                    SalesDiscountAccountCode = table.Column<string>(type: "varchar(20)", maxLength: 20, nullable: true, collation: "utf8mb4_unicode_ci"),
+                    InventoryGainAccountCode = table.Column<string>(type: "varchar(20)", maxLength: 20, nullable: true, collation: "utf8mb4_unicode_ci"),
+                    CogsAccountCode = table.Column<string>(type: "varchar(20)", maxLength: 20, nullable: true, collation: "utf8mb4_unicode_ci"),
+                    InventoryLossAccountCode = table.Column<string>(type: "varchar(20)", maxLength: 20, nullable: true, collation: "utf8mb4_unicode_ci"),
+                    CashAccountCode = table.Column<string>(type: "varchar(20)", maxLength: 20, nullable: true, collation: "utf8mb4_unicode_ci"),
+                    UpdatedAt = table.Column<DateTime>(type: "datetime(6)", nullable: true),
+                    UpdatedBy = table.Column<int>(type: "int", nullable: true),
+                    RowVersion = table.Column<uint>(type: "int unsigned", nullable: false)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_gl_account_config", x => x.ConfigId);
+                    table.CheckConstraint("ck_gl_account_config_singleton", "`ConfigId` = 1");
+                    table.ForeignKey(
+                        name: "FK_gl_account_config_users_UpdatedBy",
+                        column: x => x.UpdatedBy,
+                        principalTable: "users",
+                        principalColumn: "UserId",
+                        onDelete: ReferentialAction.Restrict);
+                })
+                .Annotation("Relational:Collation", "utf8mb4_unicode_ci");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_gl_account_config_UpdatedBy",
+                table: "gl_account_config",
+                column: "UpdatedBy");
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropTable(
+                name: "gl_account_config");
+        }
+    }
+}

Backend/ERPCore/Migrations/ErpDbContextModelSnapshot.cs

@@ -1421,6 +1421,79 @@ namespace ERPCore.Migrations
                     b.ToTable("hr_employment_types", (string)null);
                 });
 
+            modelBuilder.Entity("ERPCore.Domain.Entities.GlAccountConfig", b =>
+                {
+                    b.Property<int>("ConfigId")
+                        .HasColumnType("int");
+
+                    b.Property<string>("AccountsPayableCode")
+                        .HasMaxLength(20)
+                        .HasColumnType("varchar(20)");
+
+                    b.Property<string>("AccountsReceivableCode")
+                        .HasMaxLength(20)
+                        .HasColumnType("varchar(20)");
+
+                    b.Property<string>("CashAccountCode")
+                        .HasMaxLength(20)
+                        .HasColumnType("varchar(20)");
+
+                    b.Property<string>("ClearingAccountCode")
+                        .HasMaxLength(20)
+                        .HasColumnType("varchar(20)");
+
+                    b.Property<string>("CogsAccountCode")
+                        .HasMaxLength(20)
+                        .HasColumnType("varchar(20)");
+
+                    b.Property<string>("InventoryAccountCode")
+                        .HasMaxLength(20)
+                        .HasColumnType("varchar(20)");
+
+                    b.Property<string>("InventoryGainAccountCode")
+                        .HasMaxLength(20)
+                        .HasColumnType("varchar(20)");
+
+                    b.Property<string>("InventoryLossAccountCode")
+                        .HasMaxLength(20)
+                        .HasColumnType("varchar(20)");
+
+                    b.Property<uint>("RowVersion")
+                        .IsConcurrencyToken()
+                        .HasColumnType("int unsigned");
+
+                    b.Property<string>("SalesDiscountAccountCode")
+                        .HasMaxLength(20)
+                        .HasColumnType("varchar(20)");
+
+                    b.Property<string>("SalesRevenueAccountCode")
+                        .HasMaxLength(20)
+                        .HasColumnType("varchar(20)");
+
+                    b.Property<string>("TaxPayableAccountCode")
+                        .HasMaxLength(20)
+                        .HasColumnType("varchar(20)");
+
+                    b.Property<DateTime?>("UpdatedAt")
+                        .HasColumnType("datetime(6)");
+
+                    b.Property<int?>("UpdatedBy")
+                        .HasColumnType("int");
+
+                    b.Property<string>("VatRecoverableAccountCode")
+                        .HasMaxLength(20)
+                        .HasColumnType("varchar(20)");
+
+                    b.HasKey("ConfigId");
+
+                    b.HasIndex("UpdatedBy");
+
+                    b.ToTable("gl_account_config", null, t =>
+                        {
+                            t.HasCheckConstraint("ck_gl_account_config_singleton", "`ConfigId` = 1");
+                        });
+                });
+
             modelBuilder.Entity("ERPCore.Domain.Entities.Grn", b =>
                 {
                     b.Property<int>("GrnId")
@@ -7117,6 +7190,16 @@ namespace ERPCore.Migrations
                     b.Navigation("SalaryComponent");
                 });
 
+            modelBuilder.Entity("ERPCore.Domain.Entities.GlAccountConfig", b =>
+                {
+                    b.HasOne("ERPCore.Domain.Entities.User", "UpdatedByUser")
+                        .WithMany()
+                        .HasForeignKey("UpdatedBy")
+                        .OnDelete(DeleteBehavior.Restrict);
+
+                    b.Navigation("UpdatedByUser");
+                });
+
             modelBuilder.Entity("ERPCore.Domain.Entities.Grn", b =>
                 {
                     b.HasOne("ERPCore.Domain.Entities.Branch", "Branch")

Backend/ERPCore/Program.cs

@@ -119,6 +119,7 @@ builder.Services.AddScoped<IProductConfigService, ProductConfigService>();
 builder.Services.AddScoped<IBranchConfigService, BranchConfigService>();
 builder.Services.AddScoped<ISalesConfigService, SalesConfigService>();
 builder.Services.AddScoped<IGrnConfigService, GrnConfigService>();
+builder.Services.AddScoped<IGlAccountConfigService, GlAccountConfigService>();
 builder.Services.AddScoped<IBranchAccessService, BranchAccessService>();
 builder.Services.AddSingleton<INotificationModuleCatalog, NotificationModuleCatalog>();
 builder.Services.AddScoped<INotificationConfigService, NotificationConfigService>();
@@ -241,7 +242,7 @@ using (var scope = app.Services.CreateScope())
     await db.Database.MigrateAsync();
     try
     {
-        await DataSeeder.SeedAsync(db);
+        await DataSeeder.SeedAsync(db, builder.Configuration);
     }
     catch (Exception ex)
     {

Backend/ERPCore/Services/AdjustmentService.cs

@@ -37,15 +37,13 @@ public sealed class AdjustmentService : IAdjustmentService
     private readonly INotificationService _notifications;
     private readonly IUnitOfWork _uow;
     private readonly IGeneralLedgerService _gl;
-    private readonly string _glInventoryAccountCode;
+    private readonly IGlAccountConfigService _glAccounts;
-    private readonly string _glGainAccountCode;
-    private readonly string _glLossAccountCode;
 
     public AdjustmentService(
         IRepository<StockAdjustment> adjustments, IRepository<Warehouse> warehouses, IRepository<Item> items,
         IRepository<ReasonCode> reasonCodes, IRepository<StockLedger> ledger, IStockMutator mutator,
         INumberSequenceService numbers, ICurrentUser currentUser, IBranchConfigService branchConfig, INotificationService notifications, IUnitOfWork uow,
-        IGeneralLedgerService gl, IConfiguration configuration)
+        IGeneralLedgerService gl, IGlAccountConfigService glAccounts)
     {
         _adjustments = adjustments;
         _warehouses = warehouses;
@@ -59,9 +57,7 @@ public sealed class AdjustmentService : IAdjustmentService
         _notifications = notifications;
         _uow = uow;
         _gl = gl;
-        _glInventoryAccountCode = configuration["Adjustment:GlInventoryAccountCode"] ?? string.Empty;
+        _glAccounts = glAccounts;
-        _glGainAccountCode = configuration["Adjustment:GlGainAccountCode"] ?? string.Empty;
-        _glLossAccountCode = configuration["Adjustment:GlLossAccountCode"] ?? string.Empty;
     }
 
     /// <summary>Builds and posts the GL journal for a <see cref="StockAdjustment"/>'s stock movement.
@@ -74,17 +70,18 @@ public sealed class AdjustmentService : IAdjustmentService
         var loss = refs.Where(r => r.Direction == Direction.Out).Sum(r => r.Value);
         if (gain <= 0 && loss <= 0) return null;
 
+        var glCodes = await _glAccounts.GetCodesAsync(ct);
         var period = await _gl.GetPeriodByDateAsync(BusinessClock.ToBusinessDate(now), ct);
         var lines = new List<GlJournalEntryLineRequest>();
         if (gain > 0)
         {
-            lines.Add(new GlJournalEntryLineRequest(_glInventoryAccountCode, gain, 0m, $"Adjustment {docNo} — stock increase"));
+            lines.Add(new GlJournalEntryLineRequest(glCodes[GlAccountRole.Inventory], gain, 0m, $"Adjustment {docNo} — stock increase"));
-            lines.Add(new GlJournalEntryLineRequest(_glGainAccountCode, 0m, gain, $"Adjustment {docNo} — inventory gain"));
+            lines.Add(new GlJournalEntryLineRequest(glCodes[GlAccountRole.InventoryGain], 0m, gain, $"Adjustment {docNo} — inventory gain"));
         }
         if (loss > 0)
         {
-            lines.Add(new GlJournalEntryLineRequest(_glLossAccountCode, loss, 0m, $"Adjustment {docNo} — inventory loss"));
+            lines.Add(new GlJournalEntryLineRequest(glCodes[GlAccountRole.InventoryLoss], loss, 0m, $"Adjustment {docNo} — inventory loss"));
-            lines.Add(new GlJournalEntryLineRequest(_glInventoryAccountCode, 0m, loss, $"Adjustment {docNo} — stock decrease"));
+            lines.Add(new GlJournalEntryLineRequest(glCodes[GlAccountRole.Inventory], 0m, loss, $"Adjustment {docNo} — stock decrease"));
         }
 
         var result = await _gl.PostJournalEntryAsync(new GlJournalEntryRequest

Backend/ERPCore/Services/CountService.cs

@@ -41,16 +41,14 @@ public sealed class CountService : ICountService
     private readonly IRepository<StockLayer> _stockLayers;
     private readonly IRepository<Batch> _batches;
     private readonly IRepository<Serial> _serials;
-    private readonly string _glInventoryAccountCode;
+    private readonly IGlAccountConfigService _glAccounts;
-    private readonly string _glGainAccountCode;
-    private readonly string _glLossAccountCode;
 
     public CountService(
         IRepository<StockCount> counts, IRepository<StockAdjustment> adjustments, IRepository<Warehouse> warehouses,
         IRepository<Item> items, IRepository<ReasonCode> reasonCodes, IFifoCostingService fifo, IStockMutator mutator,
         INumberSequenceService numbers, ICurrentUser currentUser, IBranchConfigService branchConfig, IUnitOfWork uow,
         IGeneralLedgerService gl, IRepository<StockLayer> stockLayers, IRepository<Batch> batches,
-        IRepository<Serial> serials, IConfiguration configuration)
+        IRepository<Serial> serials, IGlAccountConfigService glAccounts)
     {
         _counts = counts;
         _adjustments = adjustments;
@@ -67,9 +65,7 @@ public sealed class CountService : ICountService
         _stockLayers = stockLayers;
         _batches = batches;
         _serials = serials;
-        _glInventoryAccountCode = configuration["Adjustment:GlInventoryAccountCode"] ?? string.Empty;
+        _glAccounts = glAccounts;
-        _glGainAccountCode = configuration["Adjustment:GlGainAccountCode"] ?? string.Empty;
-        _glLossAccountCode = configuration["Adjustment:GlLossAccountCode"] ?? string.Empty;
     }
 
     /// <summary>Same logic as <c>AdjustmentService</c>'s private method of the same name — see there for why
@@ -81,17 +77,18 @@ public sealed class CountService : ICountService
         var loss = refs.Where(r => r.Direction == Direction.Out).Sum(r => r.Value);
         if (gain <= 0 && loss <= 0) return null;
 
+        var glCodes = await _glAccounts.GetCodesAsync(ct);
         var period = await _gl.GetPeriodByDateAsync(BusinessClock.ToBusinessDate(now), ct);
         var lines = new List<GlJournalEntryLineRequest>();
         if (gain > 0)
         {
-            lines.Add(new GlJournalEntryLineRequest(_glInventoryAccountCode, gain, 0m, $"Adjustment {docNo} — stock increase"));
+            lines.Add(new GlJournalEntryLineRequest(glCodes[GlAccountRole.Inventory], gain, 0m, $"Adjustment {docNo} — stock increase"));
-            lines.Add(new GlJournalEntryLineRequest(_glGainAccountCode, 0m, gain, $"Adjustment {docNo} — inventory gain"));
+            lines.Add(new GlJournalEntryLineRequest(glCodes[GlAccountRole.InventoryGain], 0m, gain, $"Adjustment {docNo} — inventory gain"));
         }
         if (loss > 0)
         {
-            lines.Add(new GlJournalEntryLineRequest(_glLossAccountCode, loss, 0m, $"Adjustment {docNo} — inventory loss"));
+            lines.Add(new GlJournalEntryLineRequest(glCodes[GlAccountRole.InventoryLoss], loss, 0m, $"Adjustment {docNo} — inventory loss"));
-            lines.Add(new GlJournalEntryLineRequest(_glInventoryAccountCode, 0m, loss, $"Adjustment {docNo} — stock decrease"));
+            lines.Add(new GlJournalEntryLineRequest(glCodes[GlAccountRole.Inventory], 0m, loss, $"Adjustment {docNo} — stock decrease"));
         }
 
         var result = await _gl.PostJournalEntryAsync(new GlJournalEntryRequest

Backend/ERPCore/Services/GeneralLedgerService.cs

@@ -49,7 +49,7 @@ public sealed class GeneralLedgerService : IGeneralLedgerService
             a.CashAccountTypeName, a.AccountNumber, a.GlAccountId, a.GlAccountCode, a.CurrencyCode)).ToList();
     }
 
-    public async Task<HashSet<string>> ListAccountCodesAsync(CancellationToken ct)
+    public async Task<IReadOnlyList<GlAccount>> ListAccountsAsync(CancellationToken ct)
     {
         // No page/pageSize: GL pages this endpoint only when both are supplied, so this is the
         // full, flat chart of accounts (child codes like "1000-01" are rows of their own —
@@ -59,8 +59,8 @@ public sealed class GeneralLedgerService : IGeneralLedgerService
         // `"items": null` deserializes over the property initialiser, so the null check is load-bearing.
         return (data.Items ?? [])
             .Where(a => a is not null && !string.IsNullOrWhiteSpace(a.AccountCode))
-            .Select(a => a.AccountCode)
+            .Select(a => new GlAccount(a.AccountCode, a.AccountName, a.AccountTypeId, a.IsPostable, a.IsActive))
-            .ToHashSet(StringComparer.Ordinal);
+            .ToList();
     }
 
     /// <summary>
@@ -118,6 +118,10 @@ public sealed class GeneralLedgerService : IGeneralLedgerService
     private sealed class GlAccountData
     {
         public string AccountCode { get; set; } = string.Empty;
+        public string AccountName { get; set; } = string.Empty;
+        public short AccountTypeId { get; set; }
+        public bool IsPostable { get; set; }
+        public bool IsActive { get; set; }
     }
 
     private sealed class GlBankAccountData

Backend/ERPCore/Services/GlAccountConfigService.cs

@@ -0,0 +1,195 @@
+using ERPCore.Common.Http;
+using ERPCore.Domain.Entities;
+using ERPCore.Dtos.Config;
+using ERPCore.Infra.Auth;
+using ERPCore.Infra.UoW;
+using ERPCore.Repositories.Interfaces;
+using ERPCore.Services.Gl;
+using ERPCore.Services.Interfaces;
+using ERPCore.System.Errors;
+using Microsoft.EntityFrameworkCore;
+
+namespace ERPCore.Services;
+
+/// <inheritdoc cref="IGlAccountConfigService"/>
+public sealed class GlAccountConfigService : IGlAccountConfigService
+{
+    private readonly IRepository<GlAccountConfig> _config;
+    private readonly IGeneralLedgerService _gl;
+    private readonly ICurrentUser _currentUser;
+    private readonly IUnitOfWork _uow;
+
+    /// <summary>Scope-lifetime cache — see <see cref="IGlAccountConfigService.GetCodesAsync"/>.</summary>
+    private GlAccountCodes? _cached;
+
+    public GlAccountConfigService(
+        IRepository<GlAccountConfig> config, IGeneralLedgerService gl, ICurrentUser currentUser, IUnitOfWork uow)
+    {
+        _config = config;
+        _gl = gl;
+        _currentUser = currentUser;
+        _uow = uow;
+    }
+
+    public async Task<ETagged<GlAccountConfigDto>> GetAsync(CancellationToken ct = default)
+    {
+        var config = await _config.Query().AsNoTracking()
+            .FirstOrDefaultAsync(c => c.ConfigId == GlAccountConfig.SingletonId, ct)
+            ?? throw new NotFoundException("GL account configuration has not been seeded.");
+
+        // Read-only screen data: GL being down must not stop the saved mapping from rendering.
+        IReadOnlyList<GlAccount> accounts = [];
+        var glUnavailable = false;
+        try
+        {
+            accounts = await _gl.ListAccountsAsync(ct);
+        }
+        catch (DomainException)
+        {
+            glUnavailable = true;
+        }
+
+        return new ETagged<GlAccountConfigDto>(Map(config, accounts, glUnavailable), config.RowVersion);
+    }
+
+    public async Task<ETagged<GlAccountConfigDto>> UpdateAsync(
+        UpdateGlAccountConfigRequest request, uint expectedRowVersion, CancellationToken ct = default)
+    {
+        var config = await _config.GetByIdAsync(GlAccountConfig.SingletonId, ct)
+            ?? throw new NotFoundException("GL account configuration has not been seeded.");
+
+        if (config.RowVersion != expectedRowVersion)
+            throw new DomainException(ErrorCodes.ConcurrencyConflict, "The configuration was modified by another request.", 412);
+
+        var submitted = Submitted(request);
+
+        // Fails closed, unlike GlAccountCodeValidator at startup: there we cannot verify and must
+        // still serve, here we cannot verify and must not store. Letting an unchecked mapping
+        // through is how the appsettings version went unnoticed for months.
+        var accounts = await _gl.ListAccountsAsync(ct);
+        if (accounts.Count == 0)
+            throw new DomainException(
+                ErrorCodes.GlAccountInvalid,
+                "GL returned an empty chart of accounts, so the mapping cannot be verified. Try again once GL has accounts.",
+                503);
+
+        var byCode = accounts.ToDictionary(a => a.AccountCode, StringComparer.Ordinal);
+        var problems = new List<string>();
+        foreach (var (role, code) in submitted)
+        {
+            if (code is null) continue;
+
+            if (!byCode.TryGetValue(code, out var account))
+                problems.Add($"{role}: account '{code}' does not exist in GL");
+            else if (!account.IsPostable)
+                // GL rejects a journal line against a non-postable account, so storing one just
+                // moves the failure to posting time. Control/header accounts are the usual trap.
+                problems.Add($"{role}: account '{code}' ({account.AccountName}) is not postable");
+        }
+
+        if (problems.Count > 0)
+            throw new DomainException(
+                ErrorCodes.GlAccountInvalid,
+                "The GL account mapping was rejected — " + string.Join("; ", problems) + ".",
+                422);
+
+        config.InventoryAccountCode = submitted[GlAccountRole.Inventory];
+        config.VatRecoverableAccountCode = submitted[GlAccountRole.VatRecoverable];
+        config.AccountsReceivableCode = submitted[GlAccountRole.AccountsReceivable];
+        config.ClearingAccountCode = submitted[GlAccountRole.Clearing];
+        config.TaxPayableAccountCode = submitted[GlAccountRole.TaxPayable];
+        config.AccountsPayableCode = submitted[GlAccountRole.AccountsPayable];
+        config.SalesRevenueAccountCode = submitted[GlAccountRole.SalesRevenue];
+        config.SalesDiscountAccountCode = submitted[GlAccountRole.SalesDiscount];
+        config.InventoryGainAccountCode = submitted[GlAccountRole.InventoryGain];
+        config.CogsAccountCode = submitted[GlAccountRole.Cogs];
+        config.InventoryLossAccountCode = submitted[GlAccountRole.InventoryLoss];
+        config.CashAccountCode = submitted[GlAccountRole.Cash];
+        config.UpdatedAt = DateTime.UtcNow;
+        config.UpdatedBy = _currentUser.AuditUserId;
+
+        try
+        {
+            await _uow.SaveChangesAsync(ct);
+        }
+        catch (DbUpdateConcurrencyException)
+        {
+            throw new DomainException(ErrorCodes.ConcurrencyConflict, "The configuration was modified by another request.", 412);
+        }
+
+        _cached = null;
+        return new ETagged<GlAccountConfigDto>(Map(config, accounts, glUnavailable: false), config.RowVersion);
+    }
+
+    public async Task<GlAccountCodes> GetCodesAsync(CancellationToken ct = default)
+    {
+        if (_cached is not null) return _cached;
+
+        var config = await _config.Query().AsNoTracking()
+            .FirstOrDefaultAsync(c => c.ConfigId == GlAccountConfig.SingletonId, ct)
+            ?? throw new NotFoundException("GL account configuration has not been seeded.");
+
+        return _cached = new GlAccountCodes(Current(config));
+    }
+
+    /// <summary>Role → stored code, normalising blanks to null.</summary>
+    private static Dictionary<GlAccountRole, string?> Current(GlAccountConfig c) => new()
+    {
+        [GlAccountRole.Inventory] = Trim(c.InventoryAccountCode),
+        [GlAccountRole.VatRecoverable] = Trim(c.VatRecoverableAccountCode),
+        [GlAccountRole.AccountsReceivable] = Trim(c.AccountsReceivableCode),
+        [GlAccountRole.Clearing] = Trim(c.ClearingAccountCode),
+        [GlAccountRole.TaxPayable] = Trim(c.TaxPayableAccountCode),
+        [GlAccountRole.AccountsPayable] = Trim(c.AccountsPayableCode),
+        [GlAccountRole.SalesRevenue] = Trim(c.SalesRevenueAccountCode),
+        [GlAccountRole.SalesDiscount] = Trim(c.SalesDiscountAccountCode),
+        [GlAccountRole.InventoryGain] = Trim(c.InventoryGainAccountCode),
+        [GlAccountRole.Cogs] = Trim(c.CogsAccountCode),
+        [GlAccountRole.InventoryLoss] = Trim(c.InventoryLossAccountCode),
+        [GlAccountRole.Cash] = Trim(c.CashAccountCode)
+    };
+
+    private static Dictionary<GlAccountRole, string?> Submitted(UpdateGlAccountConfigRequest r) => new()
+    {
+        [GlAccountRole.Inventory] = Trim(r.InventoryAccountCode),
+        [GlAccountRole.VatRecoverable] = Trim(r.VatRecoverableAccountCode),
+        [GlAccountRole.AccountsReceivable] = Trim(r.AccountsReceivableCode),
+        [GlAccountRole.Clearing] = Trim(r.ClearingAccountCode),
+        [GlAccountRole.TaxPayable] = Trim(r.TaxPayableAccountCode),
+        [GlAccountRole.AccountsPayable] = Trim(r.AccountsPayableCode),
+        [GlAccountRole.SalesRevenue] = Trim(r.SalesRevenueAccountCode),
+        [GlAccountRole.SalesDiscount] = Trim(r.SalesDiscountAccountCode),
+        [GlAccountRole.InventoryGain] = Trim(r.InventoryGainAccountCode),
+        [GlAccountRole.Cogs] = Trim(r.CogsAccountCode),
+        [GlAccountRole.InventoryLoss] = Trim(r.InventoryLossAccountCode),
+        [GlAccountRole.Cash] = Trim(r.CashAccountCode)
+    };
+
+    private static string? Trim(string? code) => string.IsNullOrWhiteSpace(code) ? null : code.Trim();
+
+    private static GlAccountConfigDto Map(
+        GlAccountConfig config, IReadOnlyList<GlAccount> accounts, bool glUnavailable)
+    {
+        var byCode = accounts.ToDictionary(a => a.AccountCode, StringComparer.Ordinal);
+
+        var mappings = Current(config).Select(kv =>
+        {
+            var found = kv.Value is not null && byCode.TryGetValue(kv.Value, out var a) ? a : null;
+            return new GlAccountMappingDto(
+                kv.Key.ToString(),
+                kv.Value,
+                found?.AccountName,
+                // Unknown while GL is down, rather than falsely "missing".
+                ExistsInGl: glUnavailable || found is not null,
+                IsPostable: glUnavailable || found?.IsPostable == true);
+        }).ToList();
+
+        var options = accounts
+            .Where(a => a.IsPostable && a.IsActive)
+            .OrderBy(a => a.AccountCode, StringComparer.Ordinal)
+            .Select(a => new GlAccountOptionDto(a.AccountCode, a.AccountName, a.AccountTypeId, a.IsPostable, a.IsActive))
+            .ToList();
+
+        return new GlAccountConfigDto(mappings, options, glUnavailable, config.UpdatedAt, config.UpdatedBy);
+    }
+}

Backend/ERPCore/Services/GrnService.cs

@@ -45,9 +45,7 @@ public sealed class GrnService : IGrnService
     private readonly IUnitOfWork _uow;
     private readonly IGeneralLedgerService _gl;
     private readonly INotificationService _notifications;
-    private readonly string _glInventoryAccountCode;
+    private readonly IGlAccountConfigService _glAccounts;
-    private readonly string _glVatRecoverableAccountCode;
-    private readonly string _glClearingAccountCode;
 
     public GrnService(
         IRepository<Grn> grns, IRepository<PurchaseOrder> pos, IRepository<PoLine> poLines,
@@ -55,7 +53,7 @@ public sealed class GrnService : IGrnService
         IRepository<Bin> bins, IRepository<Vendor> vendors, IRepository<Batch> batches,
         IRepository<StockLayer> layers, IRepository<StockLedger> ledger, IRepository<TaxRate> taxRates,
         IFifoCostingService fifo, INumberSequenceService numbers, ICurrentUser currentUser, IBranchConfigService branchConfig, IGrnConfigService grnConfig,
-        IUnitOfWork uow, IGeneralLedgerService gl, INotificationService notifications, IConfiguration configuration)
+        IUnitOfWork uow, IGeneralLedgerService gl, INotificationService notifications, IGlAccountConfigService glAccounts)
     {
         _grns = grns;
         _pos = pos;
@@ -76,9 +74,7 @@ public sealed class GrnService : IGrnService
         _uow = uow;
         _gl = gl;
         _notifications = notifications;
-        _glInventoryAccountCode = configuration["Grn:GlInventoryAccountCode"] ?? string.Empty;
+        _glAccounts = glAccounts;
-        _glVatRecoverableAccountCode = configuration["Grn:GlVatRecoverableAccountCode"] ?? string.Empty;
-        _glClearingAccountCode = configuration["Grn:GlClearingAccountCode"] ?? string.Empty;
     }
 
     public async Task<PagedResponse<GrnSummaryDto>> ListAsync(
@@ -311,17 +307,18 @@ public sealed class GrnService : IGrnService
             // with it, so inventory and the ledger never diverge (user-approved "fails
             // atomically" behavior; residual risk if GL posts but the local commit still
             // fails afterward is accepted for this phase, see the integration plan).
+            var glCodes = await _glAccounts.GetCodesAsync(token);
             var period = await _gl.GetPeriodByDateAsync(BusinessClock.ToBusinessDate(now), token);
             var glLines = new List<GlJournalEntryLineRequest>();
             decimal totalPayable = 0m;
             foreach (var line in grn.Lines.OrderBy(l => l.GrnLineId))
             {
-                glLines.Add(new GlJournalEntryLineRequest(_glInventoryAccountCode, line.ReceivedValue, 0m, $"GRN {grn.DocNo} line {line.GrnLineId}"));
+                glLines.Add(new GlJournalEntryLineRequest(glCodes[GlAccountRole.Inventory], line.ReceivedValue, 0m, $"GRN {grn.DocNo} line {line.GrnLineId}"));
                 if (line.VatAmount > 0)
-                    glLines.Add(new GlJournalEntryLineRequest(_glVatRecoverableAccountCode, line.VatAmount, 0m, $"GRN {grn.DocNo} line {line.GrnLineId} VAT"));
+                    glLines.Add(new GlJournalEntryLineRequest(glCodes[GlAccountRole.VatRecoverable], line.VatAmount, 0m, $"GRN {grn.DocNo} line {line.GrnLineId} VAT"));
                 totalPayable += line.LineTotal;
             }
-            glLines.Add(new GlJournalEntryLineRequest(_glClearingAccountCode, 0m, totalPayable, $"GRN {grn.DocNo} received"));
+            glLines.Add(new GlJournalEntryLineRequest(glCodes[GlAccountRole.Clearing], 0m, totalPayable, $"GRN {grn.DocNo} received"));
 
             var posted = await _gl.PostJournalEntryAsync(new GlJournalEntryRequest
             {

Backend/ERPCore/Services/Interfaces/IGlAccountConfigService.cs

@@ -0,0 +1,30 @@
+using ERPCore.Common.Http;
+using ERPCore.Dtos.Config;
+using ERPCore.Services.Gl;
+
+namespace ERPCore.Services.Interfaces;
+
+/// <summary>
+/// The role → GL account code mapping: master data, held in <c>gl_account_config</c> and validated
+/// against GL's live chart of accounts on save. Replaces the per-module <c>Gl*Code</c> appsettings
+/// keys, which could only be checked at boot and only after a redeploy could be corrected.
+/// </summary>
+public interface IGlAccountConfigService
+{
+    /// <summary>Current mapping plus the selectable accounts, for the settings screen.</summary>
+    Task<ETagged<GlAccountConfigDto>> GetAsync(CancellationToken ct = default);
+
+    /// <summary>
+    /// Replaces the mapping. Fails closed: rejects any code GL does not have or cannot post to, and
+    /// rejects the save outright if GL cannot be reached — an unverified mapping is not a valid one.
+    /// </summary>
+    Task<ETagged<GlAccountConfigDto>> UpdateAsync(
+        UpdateGlAccountConfigRequest request, uint expectedRowVersion, CancellationToken ct = default);
+
+    /// <summary>
+    /// The mapping as posting flows consume it. Cached for the lifetime of the scope — a single
+    /// request can post through several services (GrnService → FifoCostingService) and they should
+    /// not each re-read the row.
+    /// </summary>
+    Task<GlAccountCodes> GetCodesAsync(CancellationToken ct = default);
+}

Backend/ERPCore/Services/PurchaseInvoicePaymentService.cs

@@ -28,18 +28,18 @@ public sealed class PurchaseInvoicePaymentService : IPurchaseInvoicePaymentServi
     private readonly IGeneralLedgerService _gl;
     private readonly ICurrentUser _currentUser;
     private readonly IUnitOfWork _uow;
-    private readonly string _glAccountsPayableCode;
+    private readonly IGlAccountConfigService _glAccounts;
 
     public PurchaseInvoicePaymentService(
         IRepository<PurchaseInvoice> invoices, IRepository<PurchaseInvoicePayment> payments, IGeneralLedgerService gl,
-        ICurrentUser currentUser, IUnitOfWork uow, IConfiguration configuration)
+        ICurrentUser currentUser, IUnitOfWork uow, IGlAccountConfigService glAccounts)
     {
         _invoices = invoices;
         _payments = payments;
         _gl = gl;
         _currentUser = currentUser;
         _uow = uow;
-        _glAccountsPayableCode = configuration["PurchaseInvoice:GlAccountsPayableCode"] ?? string.Empty;
+        _glAccounts = glAccounts;
     }
 
     public async Task<PurchaseInvoicePaymentDto> PayAsync(int purchaseInvoiceId, CreatePurchaseInvoicePaymentRequest request, CancellationToken ct = default)
@@ -62,6 +62,7 @@ public sealed class PurchaseInvoicePaymentService : IPurchaseInvoicePaymentServi
 
         var payment = await _uow.ExecuteInTransactionAsync(async token =>
         {
+            var glCodes = await _glAccounts.GetCodesAsync(token);
             var period = await _gl.GetPeriodByDateAsync(BusinessClock.ToBusinessDate(now), token);
             var posted = await _gl.PostJournalEntryAsync(new GlJournalEntryRequest
             {
@@ -72,7 +73,7 @@ public sealed class PurchaseInvoicePaymentService : IPurchaseInvoicePaymentServi
                 Narration = $"Payment against invoice {invoice.DocNo}",
                 Lines =
                 [
-                    new GlJournalEntryLineRequest(_glAccountsPayableCode, request.Amount, 0m, $"Payment against invoice {invoice.DocNo}"),
+                    new GlJournalEntryLineRequest(glCodes[GlAccountRole.AccountsPayable], request.Amount, 0m, $"Payment against invoice {invoice.DocNo}"),
                     new GlJournalEntryLineRequest(account.GlAccountCode, 0m, request.Amount, $"Payment against invoice {invoice.DocNo}")
                 ]
             }, token);

Backend/ERPCore/Services/PurchaseInvoiceService.cs

@@ -35,13 +35,12 @@ public sealed class PurchaseInvoiceService : IPurchaseInvoiceService
     private readonly INumberSequenceService _numbers;
     private readonly IUnitOfWork _uow;
     private readonly IGeneralLedgerService _gl;
-    private readonly string _glClearingAccountCode;
+    private readonly IGlAccountConfigService _glAccounts;
-    private readonly string _glAccountsPayableCode;
 
     public PurchaseInvoiceService(
         IRepository<PurchaseInvoice> invoices, IRepository<Vendor> vendors, IRepository<Grn> grns,
         ICurrentUser currentUser, INumberSequenceService numbers, IUnitOfWork uow,
-        IGeneralLedgerService gl, IConfiguration configuration)
+        IGeneralLedgerService gl, IGlAccountConfigService glAccounts)
     {
         _invoices = invoices;
         _vendors = vendors;
@@ -50,8 +49,7 @@ public sealed class PurchaseInvoiceService : IPurchaseInvoiceService
         _numbers = numbers;
         _uow = uow;
         _gl = gl;
-        _glClearingAccountCode = configuration["PurchaseInvoice:GlClearingAccountCode"] ?? string.Empty;
+        _glAccounts = glAccounts;
-        _glAccountsPayableCode = configuration["PurchaseInvoice:GlAccountsPayableCode"] ?? string.Empty;
     }
 
     public async Task<PagedResponse<PurchaseInvoiceSummaryDto>> ListAsync(PageQuery query, PurchaseInvoiceStatus? status, int? vendorId, CancellationToken ct = default)
@@ -186,6 +184,7 @@ public sealed class PurchaseInvoiceService : IPurchaseInvoiceService
             // Reclassify the GRN clearing balance to Accounts Payable — the mirror image of
             // SalesInvoicePaymentService's AR credit — before committing, so a GL rejection
             // rolls the whole post back (same atomicity approach as GrnService.ConfirmAsync).
+            var glCodes = await _glAccounts.GetCodesAsync(token);
             var period = await _gl.GetPeriodByDateAsync(BusinessClock.ToBusinessDate(now), token);
             var posted = await _gl.PostJournalEntryAsync(new GlJournalEntryRequest
             {
@@ -196,8 +195,8 @@ public sealed class PurchaseInvoiceService : IPurchaseInvoiceService
                 Narration = $"Vendor invoice recognized - {invoice.DocNo}",
                 Lines =
                 [
-                    new GlJournalEntryLineRequest(_glClearingAccountCode, invoice.GrandTotal, 0m, $"Purchase invoice {invoice.DocNo}"),
+                    new GlJournalEntryLineRequest(glCodes[GlAccountRole.Clearing], invoice.GrandTotal, 0m, $"Purchase invoice {invoice.DocNo}"),
-                    new GlJournalEntryLineRequest(_glAccountsPayableCode, 0m, invoice.GrandTotal, $"Purchase invoice {invoice.DocNo}")
+                    new GlJournalEntryLineRequest(glCodes[GlAccountRole.AccountsPayable], 0m, invoice.GrandTotal, $"Purchase invoice {invoice.DocNo}")
                 ]
             }, token);
 

Backend/ERPCore/Services/PurchaseReturnService.cs

@@ -43,15 +43,14 @@ public sealed class PurchaseReturnService : IPurchaseReturnService
     private readonly INotificationService _notifications;
     private readonly IUnitOfWork _uow;
     private readonly IGeneralLedgerService _gl;
-    private readonly string _glInventoryAccountCode;
+    private readonly IGlAccountConfigService _glAccounts;
-    private readonly string _glClearingAccountCode;
 
     public PurchaseReturnService(
         IRepository<PurchaseReturn> returns, IRepository<Vendor> vendors, IRepository<Warehouse> warehouses,
         IRepository<Item> items, IRepository<ReasonCode> reasonCodes, IRepository<GrnLine> grnLines,
         IRepository<StockLayer> layers, IRepository<StockLedger> ledger, IStockMutator mutator, IFifoCostingService fifo,
         INumberSequenceService numbers, ICurrentUser currentUser, INotificationService notifications,
-        IUnitOfWork uow, IGeneralLedgerService gl, IConfiguration configuration)
+        IUnitOfWork uow, IGeneralLedgerService gl, IGlAccountConfigService glAccounts)
     {
         _returns = returns;
         _vendors = vendors;
@@ -68,8 +67,7 @@ public sealed class PurchaseReturnService : IPurchaseReturnService
         _notifications = notifications;
         _uow = uow;
         _gl = gl;
-        _glInventoryAccountCode = configuration["Grn:GlInventoryAccountCode"] ?? string.Empty;
+        _glAccounts = glAccounts;
-        _glClearingAccountCode = configuration["Grn:GlClearingAccountCode"] ?? string.Empty;
     }
 
     public async Task<PagedResponse<PurchaseReturnSummaryDto>> ListAsync(
@@ -221,6 +219,7 @@ public sealed class PurchaseReturnService : IPurchaseReturnService
             var totalValue = refs.Sum(r => r.Value);
             if (totalValue > 0)
             {
+                var glCodes = await _glAccounts.GetCodesAsync(token);
                 var period = await _gl.GetPeriodByDateAsync(BusinessClock.ToBusinessDate(now), token);
                 var glResult = await _gl.PostJournalEntryAsync(new GlJournalEntryRequest
                 {
@@ -231,8 +230,8 @@ public sealed class PurchaseReturnService : IPurchaseReturnService
                     Narration = $"Purchase return {docNo} — stock returned to vendor",
                     Lines = new List<GlJournalEntryLineRequest>
                     {
-                        new(_glClearingAccountCode, totalValue, 0m, $"Purchase return {docNo}"),
+                        new(glCodes[GlAccountRole.Clearing], totalValue, 0m, $"Purchase return {docNo}"),
-                        new(_glInventoryAccountCode, 0m, totalValue, $"Purchase return {docNo} — inventory reduction")
+                        new(glCodes[GlAccountRole.Inventory], 0m, totalValue, $"Purchase return {docNo} — inventory reduction")
                     }
                 }, token);
                 ret.GlJournalNo = glResult.JournalNo;

Backend/ERPCore/Services/SalesDayEndService.cs

@@ -43,18 +43,12 @@ public sealed class SalesDayEndService : ISalesDayEndService
     private readonly ICurrentUser _currentUser;
     private readonly IUnitOfWork _uow;
     private readonly IGeneralLedgerService _gl;
-    private readonly string _glCashAccountCode;
+    private readonly IGlAccountConfigService _glAccounts;
-    private readonly string _glSalesRevenueAccountCode;
-    private readonly string _glSalesDiscountAccountCode;
-    private readonly string _glTaxPayableAccountCode;
-    private readonly string _glCogsAccountCode;
-    private readonly string _glInventoryAccountCode;
-    private readonly string _glAccountsReceivableCode;
 
     public SalesDayEndService(
         IRepository<SalesDayEnd> dayEnds, IRepository<SalesSlip> slips, IRepository<BundleSale> bundles,
         IRepository<SalesInvoice> invoices, IRepository<StockLedger> ledger, IRepository<Item> items, INumberSequenceService numbers,
-        ICurrentUser currentUser, IUnitOfWork uow, IGeneralLedgerService gl, IConfiguration configuration)
+        ICurrentUser currentUser, IUnitOfWork uow, IGeneralLedgerService gl, IGlAccountConfigService glAccounts)
     {
         _dayEnds = dayEnds;
         _slips = slips;
@@ -66,13 +60,7 @@ public sealed class SalesDayEndService : ISalesDayEndService
         _currentUser = currentUser;
         _uow = uow;
         _gl = gl;
-        _glCashAccountCode = configuration["SalesDayEnd:GlCashAccountCode"] ?? string.Empty;
+        _glAccounts = glAccounts;
-        _glSalesRevenueAccountCode = configuration["SalesDayEnd:GlSalesRevenueAccountCode"] ?? string.Empty;
-        _glSalesDiscountAccountCode = configuration["SalesDayEnd:GlSalesDiscountAccountCode"] ?? string.Empty;
-        _glTaxPayableAccountCode = configuration["SalesDayEnd:GlTaxPayableAccountCode"] ?? string.Empty;
-        _glCogsAccountCode = configuration["SalesDayEnd:GlCogsAccountCode"] ?? string.Empty;
-        _glInventoryAccountCode = configuration["SalesDayEnd:GlInventoryAccountCode"] ?? string.Empty;
-        _glAccountsReceivableCode = configuration["SalesDayEnd:GlAccountsReceivableCode"] ?? string.Empty;
     }
 
     public async Task<SalesDayEndPreviewDto> PreviewAsync(int cashierUserId, DateOnly businessDate, CancellationToken ct = default)
@@ -206,24 +194,25 @@ public sealed class SalesDayEndService : ISalesDayEndService
 
             if (grandTotal > 0 || cogs > 0)
             {
+                var glCodes = await _glAccounts.GetCodesAsync(token);
                 var period = await _gl.GetPeriodByDateAsync(businessDate, token);
                 var glLines = new List<GlJournalEntryLineRequest>();
                 if (grandTotal > 0)
                 {
                     if (paidTotal > 0)
-                        glLines.Add(new GlJournalEntryLineRequest(_glCashAccountCode, paidTotal, 0m, $"Day-end {businessDate:yyyy-MM-dd} cashier {request.CashierUserId} — cash collected"));
+                        glLines.Add(new GlJournalEntryLineRequest(glCodes[GlAccountRole.Cash], paidTotal, 0m, $"Day-end {businessDate:yyyy-MM-dd} cashier {request.CashierUserId} — cash collected"));
                     if (balanceTotal > 0)
-                        glLines.Add(new GlJournalEntryLineRequest(_glAccountsReceivableCode, balanceTotal, 0m, $"Day-end {businessDate:yyyy-MM-dd} cashier {request.CashierUserId} — sold on account"));
+                        glLines.Add(new GlJournalEntryLineRequest(glCodes[GlAccountRole.AccountsReceivable], balanceTotal, 0m, $"Day-end {businessDate:yyyy-MM-dd} cashier {request.CashierUserId} — sold on account"));
                     if (discountTotal > 0)
-                        glLines.Add(new GlJournalEntryLineRequest(_glSalesDiscountAccountCode, discountTotal, 0m, "Sales discount"));
+                        glLines.Add(new GlJournalEntryLineRequest(glCodes[GlAccountRole.SalesDiscount], discountTotal, 0m, "Sales discount"));
-                    glLines.Add(new GlJournalEntryLineRequest(_glSalesRevenueAccountCode, 0m, subtotal, "Sales revenue"));
+                    glLines.Add(new GlJournalEntryLineRequest(glCodes[GlAccountRole.SalesRevenue], 0m, subtotal, "Sales revenue"));
                     if (taxTotal > 0)
-                        glLines.Add(new GlJournalEntryLineRequest(_glTaxPayableAccountCode, 0m, taxTotal, "Output tax payable"));
+                        glLines.Add(new GlJournalEntryLineRequest(glCodes[GlAccountRole.TaxPayable], 0m, taxTotal, "Output tax payable"));
                 }
                 if (cogs > 0)
                 {
-                    glLines.Add(new GlJournalEntryLineRequest(_glCogsAccountCode, cogs, 0m, "Cost of goods sold"));
+                    glLines.Add(new GlJournalEntryLineRequest(glCodes[GlAccountRole.Cogs], cogs, 0m, "Cost of goods sold"));
-                    glLines.Add(new GlJournalEntryLineRequest(_glInventoryAccountCode, 0m, cogs, "Inventory reduction"));
+                    glLines.Add(new GlJournalEntryLineRequest(glCodes[GlAccountRole.Inventory], 0m, cogs, "Inventory reduction"));
                 }
 
                 var glResult = await _gl.PostJournalEntryAsync(new GlJournalEntryRequest

Backend/ERPCore/Services/SalesInvoicePaymentService.cs

@@ -29,11 +29,11 @@ public sealed class SalesInvoicePaymentService : ISalesInvoicePaymentService
     private readonly IGeneralLedgerService _gl;
     private readonly ICurrentUser _currentUser;
     private readonly IUnitOfWork _uow;
-    private readonly string _glAccountsReceivableCode;
+    private readonly IGlAccountConfigService _glAccounts;
 
     public SalesInvoicePaymentService(
         IRepository<SalesInvoice> invoices, IRepository<SalesInvoicePayment> payments, IRepository<SalesConfig> salesConfig,
-        IGeneralLedgerService gl, ICurrentUser currentUser, IUnitOfWork uow, IConfiguration configuration)
+        IGeneralLedgerService gl, ICurrentUser currentUser, IUnitOfWork uow, IGlAccountConfigService glAccounts)
     {
         _invoices = invoices;
         _payments = payments;
@@ -41,7 +41,7 @@ public sealed class SalesInvoicePaymentService : ISalesInvoicePaymentService
         _gl = gl;
         _currentUser = currentUser;
         _uow = uow;
-        _glAccountsReceivableCode = configuration["SalesInvoice:GlAccountsReceivableCode"] ?? string.Empty;
+        _glAccounts = glAccounts;
     }
 
     public async Task<SalesInvoicePaymentDto> PayAsync(int salesInvoiceId, CreateSalesInvoicePaymentRequest request, CancellationToken ct = default)
@@ -68,6 +68,7 @@ public sealed class SalesInvoicePaymentService : ISalesInvoicePaymentService
             // Same atomicity approach as GrnPaymentService.PayAsync: post to GL first, inside
             // this transaction, before anything is committed — a GL rejection/timeout rolls
             // the whole payment back with no partial local state.
+            var glCodes = await _glAccounts.GetCodesAsync(token);
             var period = await _gl.GetPeriodByDateAsync(paymentDay, token);
             var posted = await _gl.PostJournalEntryAsync(new GlJournalEntryRequest
             {
@@ -79,7 +80,7 @@ public sealed class SalesInvoicePaymentService : ISalesInvoicePaymentService
                 Lines =
                 [
                     new GlJournalEntryLineRequest(account.GlAccountCode, request.Amount, 0m, $"Payment against invoice {invoice.InvoiceNo}"),
-                    new GlJournalEntryLineRequest(_glAccountsReceivableCode, 0m, request.Amount, $"Payment against invoice {invoice.InvoiceNo}")
+                    new GlJournalEntryLineRequest(glCodes[GlAccountRole.AccountsReceivable], 0m, request.Amount, $"Payment against invoice {invoice.InvoiceNo}")
                 ]
             }, token);
 
@@ -178,10 +179,11 @@ public sealed class SalesInvoicePaymentService : ISalesInvoicePaymentService
         {
             // One journal for the whole payment (Debit each cash/bank line / Credit AR in total), posted
             // before anything is committed — so a GL rejection leaves neither GL nor local state half-done.
+            var glCodes = await _glAccounts.GetCodesAsync(token);
             var period = await _gl.GetPeriodByDateAsync(paymentDay, token);
             var glLines = lines
                 .Select(x => new GlJournalEntryLineRequest(x.Account.GlAccountCode, x.Line.Amount, 0m, narration))
-                .Append(new GlJournalEntryLineRequest(_glAccountsReceivableCode, 0m, total, narration))
+                .Append(new GlJournalEntryLineRequest(glCodes[GlAccountRole.AccountsReceivable], 0m, total, narration))
                 .ToList();
             var posted = await _gl.PostJournalEntryAsync(new GlJournalEntryRequest
             {

Backend/ERPCore/Services/SalesPostingService.cs

@@ -26,12 +26,7 @@ public sealed class SalesPostingService : ISalesPostingService
     private readonly ICurrentUser _currentUser;
     private readonly IUnitOfWork _uow;
     private readonly IGeneralLedgerService _gl;
-    private readonly string _glAccountsReceivableCode;
+    private readonly IGlAccountConfigService _glAccounts;
-    private readonly string _glSalesRevenueAccountCode;
-    private readonly string _glSalesDiscountAccountCode;
-    private readonly string _glTaxPayableAccountCode;
-    private readonly string _glCogsAccountCode;
-    private readonly string _glInventoryAccountCode;
 
     public SalesPostingService(
         IRepository<SalesInvoice> invoices,
@@ -44,7 +39,7 @@ public sealed class SalesPostingService : ISalesPostingService
         ICurrentUser currentUser,
         IUnitOfWork uow,
         IGeneralLedgerService gl,
-        IConfiguration configuration)
+        IGlAccountConfigService glAccounts)
     {
         _invoices = invoices;
         _slips = slips;
@@ -56,14 +51,9 @@ public sealed class SalesPostingService : ISalesPostingService
         _currentUser = currentUser;
         _uow = uow;
         _gl = gl;
-        _glAccountsReceivableCode = configuration["SalesInvoice:GlAccountsReceivableCode"] ?? string.Empty;
+        _glAccounts = glAccounts;
         // Same physical accounts Sales Day End credits for slip/bundle revenue — an invoice
         // just recognizes them immediately on Post instead of waiting for the day's close.
-        _glSalesRevenueAccountCode = configuration["SalesDayEnd:GlSalesRevenueAccountCode"] ?? string.Empty;
-        _glSalesDiscountAccountCode = configuration["SalesDayEnd:GlSalesDiscountAccountCode"] ?? string.Empty;
-        _glTaxPayableAccountCode = configuration["SalesDayEnd:GlTaxPayableAccountCode"] ?? string.Empty;
-        _glCogsAccountCode = configuration["SalesDayEnd:GlCogsAccountCode"] ?? string.Empty;
-        _glInventoryAccountCode = configuration["SalesDayEnd:GlInventoryAccountCode"] ?? string.Empty;
     }
 
     public async Task<SalesInvoicePostingCheckDto> CheckInvoiceAsync(int salesInvoiceId, CancellationToken ct = default)
@@ -185,21 +175,22 @@ public sealed class SalesPostingService : ISalesPostingService
         if (invoice.NetPayable <= 0 && cogs <= 0) return;
 
         var now = DateTime.UtcNow;
+        var glCodes = await _glAccounts.GetCodesAsync(ct);
         var period = await _gl.GetPeriodByDateAsync(BusinessClock.ToBusinessDate(now), ct);
         var lines = new List<GlJournalEntryLineRequest>();
         if (invoice.NetPayable > 0)
         {
-            lines.Add(new GlJournalEntryLineRequest(_glAccountsReceivableCode, invoice.NetPayable, 0m, $"Invoice {invoice.InvoiceNo}"));
+            lines.Add(new GlJournalEntryLineRequest(glCodes[GlAccountRole.AccountsReceivable], invoice.NetPayable, 0m, $"Invoice {invoice.InvoiceNo}"));
             if (invoice.DiscountTotal > 0)
-                lines.Add(new GlJournalEntryLineRequest(_glSalesDiscountAccountCode, invoice.DiscountTotal, 0m, "Sales discount"));
+                lines.Add(new GlJournalEntryLineRequest(glCodes[GlAccountRole.SalesDiscount], invoice.DiscountTotal, 0m, "Sales discount"));
-            lines.Add(new GlJournalEntryLineRequest(_glSalesRevenueAccountCode, 0m, invoice.Subtotal, "Sales revenue"));
+            lines.Add(new GlJournalEntryLineRequest(glCodes[GlAccountRole.SalesRevenue], 0m, invoice.Subtotal, "Sales revenue"));
             if (invoice.TaxTotal > 0)
-                lines.Add(new GlJournalEntryLineRequest(_glTaxPayableAccountCode, 0m, invoice.TaxTotal, "Output tax payable"));
+                lines.Add(new GlJournalEntryLineRequest(glCodes[GlAccountRole.TaxPayable], 0m, invoice.TaxTotal, "Output tax payable"));
         }
         if (cogs > 0)
         {
-            lines.Add(new GlJournalEntryLineRequest(_glCogsAccountCode, cogs, 0m, "Cost of goods sold"));
+            lines.Add(new GlJournalEntryLineRequest(glCodes[GlAccountRole.Cogs], cogs, 0m, "Cost of goods sold"));
-            lines.Add(new GlJournalEntryLineRequest(_glInventoryAccountCode, 0m, cogs, "Inventory reduction"));
+            lines.Add(new GlJournalEntryLineRequest(glCodes[GlAccountRole.Inventory], 0m, cogs, "Inventory reduction"));
         }
 
         var result = await _gl.PostJournalEntryAsync(new GlJournalEntryRequest

Backend/ERPCore/Services/SalesReturnService.cs

@@ -39,15 +39,14 @@ public sealed class SalesReturnService : ISalesReturnService
     private readonly ICurrentUser _currentUser;
     private readonly IUnitOfWork _uow;
     private readonly IGeneralLedgerService _gl;
-    private readonly string _glInventoryAccountCode;
+    private readonly IGlAccountConfigService _glAccounts;
-    private readonly string _glCogsAccountCode;
 
     public SalesReturnService(
         IRepository<SalesReturn> returns, IRepository<Customer> customers, IRepository<Warehouse> warehouses,
         IRepository<Item> items, IRepository<ReasonCode> reasonCodes, IRepository<SalesInvoiceLine> salesInvoiceLines,
         IRepository<SalesReturnLine> returnLines, IRepository<StockLedger> ledger, IStockMutator mutator,
         INumberSequenceService numbers, ICurrentUser currentUser, IUnitOfWork uow,
-        IGeneralLedgerService gl, IConfiguration configuration)
+        IGeneralLedgerService gl, IGlAccountConfigService glAccounts)
     {
         _returns = returns;
         _customers = customers;
@@ -62,8 +61,7 @@ public sealed class SalesReturnService : ISalesReturnService
         _currentUser = currentUser;
         _uow = uow;
         _gl = gl;
-        _glInventoryAccountCode = configuration["SalesDayEnd:GlInventoryAccountCode"] ?? string.Empty;
+        _glAccounts = glAccounts;
-        _glCogsAccountCode = configuration["SalesDayEnd:GlCogsAccountCode"] ?? string.Empty;
     }
 
     public async Task<PagedResponse<SalesReturnSummaryDto>> ListAsync(
@@ -180,6 +178,7 @@ public sealed class SalesReturnService : ISalesReturnService
             var totalValue = refs.Sum(r => r.Value);
             if (totalValue > 0)
             {
+                var glCodes = await _glAccounts.GetCodesAsync(token);
                 var period = await _gl.GetPeriodByDateAsync(BusinessClock.ToBusinessDate(now), token);
                 var glResult = await _gl.PostJournalEntryAsync(new GlJournalEntryRequest
                 {
@@ -190,8 +189,8 @@ public sealed class SalesReturnService : ISalesReturnService
                     Narration = $"Sales return {docNo} — stock restocked",
                     Lines = new List<GlJournalEntryLineRequest>
                     {
-                        new(_glInventoryAccountCode, totalValue, 0m, $"Sales return {docNo}"),
+                        new(glCodes[GlAccountRole.Inventory], totalValue, 0m, $"Sales return {docNo}"),
-                        new(_glCogsAccountCode, 0m, totalValue, $"Sales return {docNo} — COGS reversal")
+                        new(glCodes[GlAccountRole.Cogs], 0m, totalValue, $"Sales return {docNo} — COGS reversal")
                     }
                 }, token);
                 ret.GlJournalNo = glResult.JournalNo;

Backend/ERPCore/Services/Stock/FifoCostingService.cs

@@ -26,21 +26,19 @@ public sealed class FifoCostingService : IFifoCostingService
     private readonly IRepository<JournalEntryStub> _journal;
     private readonly ErpDbContext _db;
     private readonly IGeneralLedgerService _gl;
-    private readonly string _glInventoryAccountCode;
+    private readonly IGlAccountConfigService _glAccounts;
-    private readonly string _glClearingAccountCode;
 
     public FifoCostingService(
         IRepository<StockLayer> layers, IRepository<StockLedger> ledger,
         IRepository<JournalEntryStub> journal, ErpDbContext db,
-        IGeneralLedgerService gl, IConfiguration configuration)
+        IGeneralLedgerService gl, IGlAccountConfigService glAccounts)
     {
         _layers = layers;
         _ledger = ledger;
         _journal = journal;
         _db = db;
         _gl = gl;
-        _glInventoryAccountCode = configuration["Fifo:GlInventoryAccountCode"] ?? string.Empty;
+        _glAccounts = glAccounts;
-        _glClearingAccountCode = configuration["Fifo:GlClearingAccountCode"] ?? string.Empty;
     }
 
     public async Task<StockLayer> CreateInboundLayerAsync(
@@ -273,10 +271,12 @@ public sealed class FifoCostingService : IFifoCostingService
         };
         await _ledger.AddAsync(entry, ct);
 
+        var glCodes = await _glAccounts.GetCodesAsync(ct);
+
         // Inbound debits Inventory / credits Clearing; outbound reverses.
         var (debit, credit) = direction == Direction.In
-            ? (_glInventoryAccountCode, _glClearingAccountCode)
+            ? (glCodes[GlAccountRole.Inventory], glCodes[GlAccountRole.Clearing])
-            : (_glClearingAccountCode, _glInventoryAccountCode);
+            : (glCodes[GlAccountRole.Clearing], glCodes[GlAccountRole.Inventory]);
 
         // Local read-only stub kept for the journal-entries listing endpoint (FR-STK-13).
         await _journal.AddAsync(new JournalEntryStub