make account service with grn

Backend/ERPCore/Controllers/GrnsController.cs

@@ -11,8 +11,13 @@ namespace ERPCore.Controllers;
 public sealed class GrnsController : ApiControllerBase
 {
     private readonly IGrnService _grns;
+    private readonly IGrnPaymentService _payments;
 
-    public GrnsController(IGrnService grns) => _grns = grns;
+    public GrnsController(IGrnService grns, IGrnPaymentService payments)
+    {
+        _grns = grns;
+        _payments = payments;
+    }
 
     /// <summary>List GRNs, newest first.</summary>
     [HttpGet]
@@ -59,4 +64,23 @@ public sealed class GrnsController : ApiControllerBase
     public async Task<ActionResult<ReleaseLineResultDto>> Release(
         int grnId, int grnLineId, [FromBody] ReleaseLineRequest request, CancellationToken ct)
         => Ok(await _grns.ReleaseLineAsync(grnId, grnLineId, request.Action, ct));
+
+    /// <summary>Pay the vendor against this GRN's balance, in full or in installments; posts a real GL journal entry.</summary>
+    [HttpPost("{grnId:int}/payments")]
+    [ProducesResponseType(typeof(GrnPaymentDto), StatusCodes.Status201Created)]
+    [ProducesResponseType(StatusCodes.Status400BadRequest)]
+    [ProducesResponseType(StatusCodes.Status404NotFound)]
+    [ProducesResponseType(StatusCodes.Status409Conflict)]
+    public async Task<ActionResult<GrnPaymentDto>> Pay(int grnId, [FromBody] CreateGrnPaymentRequest request, CancellationToken ct)
+    {
+        var dto = await _payments.PayAsync(grnId, request, ct);
+        return Created($"/api/v1/grns/{grnId}/payments/{dto.GrnPaymentId}", dto);
+    }
+
+    /// <summary>Payment history for this GRN, newest first.</summary>
+    [HttpGet("{grnId:int}/payments")]
+    [ProducesResponseType(typeof(IReadOnlyList<GrnPaymentDto>), StatusCodes.Status200OK)]
+    [ProducesResponseType(StatusCodes.Status404NotFound)]
+    public async Task<ActionResult<IReadOnlyList<GrnPaymentDto>>> ListPayments(int grnId, CancellationToken ct)
+        => Ok(await _payments.ListAsync(grnId, ct));
 }

Backend/ERPCore/Domain/Entities/Grn.cs

@@ -30,8 +30,18 @@ public class Grn
     public DateTime CreatedAt { get; set; }
     public DateTime? PostedAt { get; set; }
 
+    /// <summary>Journal number of the real GL journal entry posted for this GRN's receipt (set on confirm).</summary>
+    public string? GlJournalNo { get; set; }
+    public DateTime? GlPostedAt { get; set; }
+
+    /// <summary>Sum of vendor payments made against this GRN's total payable (<see cref="GrnLine.LineTotal"/>).</summary>
+    public decimal PaidAmount { get; set; }
+    /// <summary>Total payable minus <see cref="PaidAmount"/>; installments accrue against this until it reaches zero.</summary>
+    public decimal BalanceAmount { get; set; }
+
     /// <summary>PostgreSQL xmin-backed optimistic concurrency token.</summary>
     public uint RowVersion { get; set; }
 
     public ICollection<GrnLine> Lines { get; set; } = new List<GrnLine>();
+    public ICollection<GrnPayment> Payments { get; set; } = new List<GrnPayment>();
 }

Backend/ERPCore/Domain/Entities/GrnPayment.cs

@@ -0,0 +1,31 @@
+namespace ERPCore.Domain.Entities;
+
+/// <summary>
+/// A vendor payment made against a confirmed GRN's balance (installments allowed —
+/// see GrnPaymentService.PayAsync). Posts its own real GL journal entry (Debit GRN
+/// Clearing / Credit the selected bank-or-cash account) before being recorded here.
+/// </summary>
+public class GrnPayment
+{
+    public int GrnPaymentId { get; set; }
+
+    public int GrnId { get; set; }
+    public Grn? Grn { get; set; }
+
+    public decimal Amount { get; set; }
+    public DateTime PaymentDate { get; set; }
+
+    /// <summary>GL's numeric id for the bank/cash account the payment was made from.</summary>
+    public long GlBankAccountId { get; set; }
+    /// <summary>Snapshot of the account's display name at payment time (GL account lists have no local FK).</summary>
+    public string BankAccountName { get; set; } = string.Empty;
+
+    public string? Reference { get; set; }
+
+    /// <summary>Journal number of the real GL journal entry this payment posted.</summary>
+    public string? GlJournalNo { get; set; }
+
+    public int CreatedBy { get; set; }
+    public User? Creator { get; set; }
+    public DateTime CreatedAt { get; set; }
+}

Backend/ERPCore/Dtos/Grn/GrnDtos.cs

@@ -16,23 +16,36 @@ public sealed record GrnLineDto(
 
 public sealed record GrnDto(
     int GrnId, string DocNo, int? PoId, int VendorId, int WarehouseId, GrnStatus Status,
-    int CreatedBy, DateTime CreatedAt, DateTime? PostedAt, IReadOnlyList<GrnLineDto> Lines);
+    int CreatedBy, DateTime CreatedAt, DateTime? PostedAt, string? GlJournalNo,
+    decimal PaidAmount, decimal BalanceAmount, IReadOnlyList<GrnLineDto> Lines);
 
 /// <summary>Row shape for <c>GET /grns</c> — line count instead of the lines themselves.</summary>
 public sealed record GrnSummaryDto(
     int GrnId, string DocNo, int? PoId, int VendorId, int WarehouseId, GrnStatus Status,
-    int CreatedBy, DateTime CreatedAt, DateTime? PostedAt, int LineCount);
+    int CreatedBy, DateTime CreatedAt, DateTime? PostedAt, int LineCount,
+    decimal PaidAmount, decimal BalanceAmount);
 
 public sealed record CreatedLayerDto(
     int LayerId, int ItemId, int WarehouseId, int? BatchId,
     decimal QtyReceived, decimal QtyRemaining, decimal UnitCost, DateTime ReceiptDate);
 
 public sealed record GrnConfirmResultDto(
-    int GrnId, GrnStatus Status, DateTime PostedAt,
+    int GrnId, GrnStatus Status, DateTime PostedAt, string GlJournalNo, decimal BalanceAmount,
     IReadOnlyList<CreatedLayerDto> CreatedLayers, IReadOnlyList<int> LedgerRefs, PurchaseOrderStatus? PoStatus);
 
 public sealed record ReleaseLineResultDto(int GrnLineId, HoldStatus HoldStatus);
 
+public sealed record GrnPaymentDto(
+    int GrnPaymentId, int GrnId, decimal Amount, DateTime PaymentDate,
+    long GlBankAccountId, string BankAccountName, string? Reference, string? GlJournalNo, DateTime CreatedAt);
+
+public sealed class CreateGrnPaymentRequest
+{
+    [Range(0.01, double.MaxValue)] public decimal Amount { get; set; }
+    [Required] public long GlBankAccountId { get; set; }
+    [StringLength(100)] public string? Reference { get; set; }
+}
+
 // Requests ----------------------------------------------------------------------
 
 public sealed class BatchInput

Backend/ERPCore/Infra/Persistence/Configurations/GrnConfiguration.cs

@@ -16,6 +16,9 @@ public sealed class GrnConfiguration : IEntityTypeConfiguration<Grn>
 
         builder.Property(g => g.Status).HasConversion<string>().HasMaxLength(20).IsRequired();
         builder.Property(g => g.CreatedAt).IsRequired();
+        builder.Property(g => g.GlJournalNo).HasMaxLength(30);
+        builder.Property(g => g.PaidAmount).HasPrecision(18, 4);
+        builder.Property(g => g.BalanceAmount).HasPrecision(18, 4);
         builder.Property(g => g.RowVersion).IsRowVersion();
 
         builder.HasOne(g => g.PurchaseOrder).WithMany().HasForeignKey(g => g.PoId).OnDelete(DeleteBehavior.Restrict);
@@ -28,6 +31,27 @@ public sealed class GrnConfiguration : IEntityTypeConfiguration<Grn>
     }
 }
 
+public sealed class GrnPaymentConfiguration : IEntityTypeConfiguration<GrnPayment>
+{
+    public void Configure(EntityTypeBuilder<GrnPayment> builder)
+    {
+        builder.ToTable("grn_payments");
+        builder.HasKey(p => p.GrnPaymentId);
+
+        builder.Property(p => p.Amount).HasPrecision(18, 4);
+        builder.Property(p => p.PaymentDate).IsRequired();
+        builder.Property(p => p.BankAccountName).IsRequired().HasMaxLength(200);
+        builder.Property(p => p.Reference).HasMaxLength(100);
+        builder.Property(p => p.GlJournalNo).HasMaxLength(30);
+        builder.Property(p => p.CreatedAt).IsRequired();
+
+        builder.HasOne(p => p.Grn).WithMany(g => g.Payments).HasForeignKey(p => p.GrnId).OnDelete(DeleteBehavior.Restrict);
+        builder.HasOne(p => p.Creator).WithMany().HasForeignKey(p => p.CreatedBy).OnDelete(DeleteBehavior.Restrict);
+
+        builder.HasIndex(p => p.GrnId);
+    }
+}
+
 public sealed class GrnLineConfiguration : IEntityTypeConfiguration<GrnLine>
 {
     public void Configure(EntityTypeBuilder<GrnLine> builder)

Backend/ERPCore/Infra/Persistence/ErpDbContext.cs

@@ -63,6 +63,7 @@ public class ErpDbContext : DbContext
     // --- Goods Receipt (docs/10 Part C.3) ---
     public DbSet<Grn> Grns => Set<Grn>();
     public DbSet<GrnLine> GrnLines => Set<GrnLine>();
+    public DbSet<GrnPayment> GrnPayments => Set<GrnPayment>();
 
     // --- Batch / Serial (docs/10 Part C.4) ---
     public DbSet<Batch> Batches => Set<Batch>();

Backend/ERPCore/Migrations/20260812091117_AddGrnGlPostingAndPayments.cs

@@ -0,0 +1,113 @@
+using System;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Npgsql.EntityFrameworkCore.PostgreSQL.Metadata;
+
+#nullable disable
+
+namespace ERPCore.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddGrnGlPostingAndPayments : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<decimal>(
+                name: "BalanceAmount",
+                table: "grns",
+                type: "numeric(18,4)",
+                precision: 18,
+                scale: 4,
+                nullable: false,
+                defaultValue: 0m);
+
+            migrationBuilder.AddColumn<string>(
+                name: "GlJournalNo",
+                table: "grns",
+                type: "character varying(30)",
+                maxLength: 30,
+                nullable: true);
+
+            migrationBuilder.AddColumn<DateTime>(
+                name: "GlPostedAt",
+                table: "grns",
+                type: "timestamp with time zone",
+                nullable: true);
+
+            migrationBuilder.AddColumn<decimal>(
+                name: "PaidAmount",
+                table: "grns",
+                type: "numeric(18,4)",
+                precision: 18,
+                scale: 4,
+                nullable: false,
+                defaultValue: 0m);
+
+            migrationBuilder.CreateTable(
+                name: "grn_payments",
+                columns: table => new
+                {
+                    GrnPaymentId = table.Column<int>(type: "integer", nullable: false)
+                        .Annotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn),
+                    GrnId = table.Column<int>(type: "integer", nullable: false),
+                    Amount = table.Column<decimal>(type: "numeric(18,4)", precision: 18, scale: 4, nullable: false),
+                    PaymentDate = table.Column<DateTime>(type: "timestamp with time zone", nullable: false),
+                    GlBankAccountId = table.Column<long>(type: "bigint", nullable: false),
+                    BankAccountName = table.Column<string>(type: "character varying(200)", maxLength: 200, nullable: false),
+                    Reference = table.Column<string>(type: "character varying(100)", maxLength: 100, nullable: true),
+                    GlJournalNo = table.Column<string>(type: "character varying(30)", maxLength: 30, nullable: true),
+                    CreatedBy = table.Column<int>(type: "integer", nullable: false),
+                    CreatedAt = table.Column<DateTime>(type: "timestamp with time zone", nullable: false)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_grn_payments", x => x.GrnPaymentId);
+                    table.ForeignKey(
+                        name: "FK_grn_payments_grns_GrnId",
+                        column: x => x.GrnId,
+                        principalTable: "grns",
+                        principalColumn: "GrnId",
+                        onDelete: ReferentialAction.Restrict);
+                    table.ForeignKey(
+                        name: "FK_grn_payments_users_CreatedBy",
+                        column: x => x.CreatedBy,
+                        principalTable: "users",
+                        principalColumn: "UserId",
+                        onDelete: ReferentialAction.Restrict);
+                });
+
+            migrationBuilder.CreateIndex(
+                name: "IX_grn_payments_CreatedBy",
+                table: "grn_payments",
+                column: "CreatedBy");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_grn_payments_GrnId",
+                table: "grn_payments",
+                column: "GrnId");
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropTable(
+                name: "grn_payments");
+
+            migrationBuilder.DropColumn(
+                name: "BalanceAmount",
+                table: "grns");
+
+            migrationBuilder.DropColumn(
+                name: "GlJournalNo",
+                table: "grns");
+
+            migrationBuilder.DropColumn(
+                name: "GlPostedAt",
+                table: "grns");
+
+            migrationBuilder.DropColumn(
+                name: "PaidAmount",
+                table: "grns");
+        }
+    }
+}

Backend/ERPCore/Migrations/ErpDbContextModelSnapshot.cs

@@ -1406,6 +1406,10 @@ namespace ERPCore.Migrations
 
                     NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<int>("GrnId"));
 
+                    b.Property<decimal>("BalanceAmount")
+                        .HasPrecision(18, 4)
+                        .HasColumnType("numeric(18,4)");
+
                     b.Property<DateTime>("CreatedAt")
                         .HasColumnType("timestamp with time zone");
 
@@ -1417,6 +1421,17 @@ namespace ERPCore.Migrations
                         .HasMaxLength(30)
                         .HasColumnType("character varying(30)");
 
+                    b.Property<string>("GlJournalNo")
+                        .HasMaxLength(30)
+                        .HasColumnType("character varying(30)");
+
+                    b.Property<DateTime?>("GlPostedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<decimal>("PaidAmount")
+                        .HasPrecision(18, 4)
+                        .HasColumnType("numeric(18,4)");
+
                     b.Property<int?>("PoId")
                         .HasColumnType("integer");
 
@@ -1537,6 +1552,55 @@ namespace ERPCore.Migrations
                     b.ToTable("grn_lines", (string)null);
                 });
 
+            modelBuilder.Entity("ERPCore.Domain.Entities.GrnPayment", b =>
+                {
+                    b.Property<int>("GrnPaymentId")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<int>("GrnPaymentId"));
+
+                    b.Property<decimal>("Amount")
+                        .HasPrecision(18, 4)
+                        .HasColumnType("numeric(18,4)");
+
+                    b.Property<string>("BankAccountName")
+                        .IsRequired()
+                        .HasMaxLength(200)
+                        .HasColumnType("character varying(200)");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<int>("CreatedBy")
+                        .HasColumnType("integer");
+
+                    b.Property<long>("GlBankAccountId")
+                        .HasColumnType("bigint");
+
+                    b.Property<string>("GlJournalNo")
+                        .HasMaxLength(30)
+                        .HasColumnType("character varying(30)");
+
+                    b.Property<int>("GrnId")
+                        .HasColumnType("integer");
+
+                    b.Property<DateTime>("PaymentDate")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("Reference")
+                        .HasMaxLength(100)
+                        .HasColumnType("character varying(100)");
+
+                    b.HasKey("GrnPaymentId");
+
+                    b.HasIndex("CreatedBy");
+
+                    b.HasIndex("GrnId");
+
+                    b.ToTable("grn_payments", (string)null);
+                });
+
             modelBuilder.Entity("ERPCore.Domain.Entities.GrnLineWarrantyNumber", b =>
                 {
                     b.Property<int>("GrnLineWarrantyNumberId")
@@ -3999,6 +4063,87 @@ namespace ERPCore.Migrations
                     b.ToTable("sales_return_lines", (string)null);
                 });
 
+            modelBuilder.Entity("ERPCore.Domain.Entities.SalesReturn", b =>
+                {
+                    b.Property<int>("ReturnId")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<int>("ReturnId"));
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<int>("CreatedBy")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("CustomerId")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("DocNo")
+                        .IsRequired()
+                        .HasMaxLength(30)
+                        .HasColumnType("character varying(30)");
+
+                    b.Property<int>("ReasonCodeId")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("Status")
+                        .IsRequired()
+                        .HasMaxLength(20)
+                        .HasColumnType("character varying(20)");
+
+                    b.Property<int>("WarehouseId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("ReturnId");
+
+                    b.HasIndex("CreatedBy");
+
+                    b.HasIndex("CustomerId");
+
+                    b.HasIndex("DocNo")
+                        .IsUnique();
+
+                    b.HasIndex("ReasonCodeId");
+
+                    b.HasIndex("WarehouseId");
+
+                    b.ToTable("sales_returns", (string)null);
+                });
+
+            modelBuilder.Entity("ERPCore.Domain.Entities.SalesReturnLine", b =>
+                {
+                    b.Property<int>("ReturnLineId")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<int>("ReturnLineId"));
+
+                    b.Property<int>("ItemId")
+                        .HasColumnType("integer");
+
+                    b.Property<decimal>("Qty")
+                        .HasPrecision(18, 4)
+                        .HasColumnType("numeric(18,4)");
+
+                    b.Property<int>("ReturnId")
+                        .HasColumnType("integer");
+
+                    b.Property<int?>("SalesInvoiceLineId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("ReturnLineId");
+
+                    b.HasIndex("ItemId");
+
+                    b.HasIndex("ReturnId");
+
+                    b.HasIndex("SalesInvoiceLineId");
+
+                    b.ToTable("sales_return_lines", (string)null);
+                });
+
             modelBuilder.Entity("ERPCore.Domain.Entities.SalesSlip", b =>
                 {
                     b.Property<int>("SalesSlipId")
@@ -5831,6 +5976,25 @@ namespace ERPCore.Migrations
                     b.Navigation("PoLine");
                 });
 
+            modelBuilder.Entity("ERPCore.Domain.Entities.GrnPayment", b =>
+                {
+                    b.HasOne("ERPCore.Domain.Entities.User", "Creator")
+                        .WithMany()
+                        .HasForeignKey("CreatedBy")
+                        .OnDelete(DeleteBehavior.Restrict)
+                        .IsRequired();
+
+                    b.HasOne("ERPCore.Domain.Entities.Grn", "Grn")
+                        .WithMany("Payments")
+                        .HasForeignKey("GrnId")
+                        .OnDelete(DeleteBehavior.Restrict)
+                        .IsRequired();
+
+                    b.Navigation("Creator");
+
+                    b.Navigation("Grn");
+                });
+
             modelBuilder.Entity("ERPCore.Domain.Entities.GrnLineWarrantyNumber", b =>
                 {
                     b.HasOne("ERPCore.Domain.Entities.GrnLine", "GrnLine")
@@ -6528,6 +6692,67 @@ namespace ERPCore.Migrations
                     b.Navigation("SalesInvoiceLine");
                 });
 
+            modelBuilder.Entity("ERPCore.Domain.Entities.SalesReturn", b =>
+                {
+                    b.HasOne("ERPCore.Domain.Entities.User", "Creator")
+                        .WithMany()
+                        .HasForeignKey("CreatedBy")
+                        .OnDelete(DeleteBehavior.Restrict)
+                        .IsRequired();
+
+                    b.HasOne("ERPCore.Domain.Entities.Customer", "Customer")
+                        .WithMany()
+                        .HasForeignKey("CustomerId")
+                        .OnDelete(DeleteBehavior.Restrict)
+                        .IsRequired();
+
+                    b.HasOne("ERPCore.Domain.Entities.ReasonCode", "ReasonCode")
+                        .WithMany()
+                        .HasForeignKey("ReasonCodeId")
+                        .OnDelete(DeleteBehavior.Restrict)
+                        .IsRequired();
+
+                    b.HasOne("ERPCore.Domain.Entities.Warehouse", "Warehouse")
+                        .WithMany()
+                        .HasForeignKey("WarehouseId")
+                        .OnDelete(DeleteBehavior.Restrict)
+                        .IsRequired();
+
+                    b.Navigation("Creator");
+
+                    b.Navigation("Customer");
+
+                    b.Navigation("ReasonCode");
+
+                    b.Navigation("Warehouse");
+                });
+
+            modelBuilder.Entity("ERPCore.Domain.Entities.SalesReturnLine", b =>
+                {
+                    b.HasOne("ERPCore.Domain.Entities.Item", "Item")
+                        .WithMany()
+                        .HasForeignKey("ItemId")
+                        .OnDelete(DeleteBehavior.Restrict)
+                        .IsRequired();
+
+                    b.HasOne("ERPCore.Domain.Entities.SalesReturn", "Return")
+                        .WithMany("Lines")
+                        .HasForeignKey("ReturnId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("ERPCore.Domain.Entities.SalesInvoiceLine", "SalesInvoiceLine")
+                        .WithMany()
+                        .HasForeignKey("SalesInvoiceLineId")
+                        .OnDelete(DeleteBehavior.Restrict);
+
+                    b.Navigation("Item");
+
+                    b.Navigation("Return");
+
+                    b.Navigation("SalesInvoiceLine");
+                });
+
             modelBuilder.Entity("ERPCore.Domain.Entities.SalesSlip", b =>
                 {
                     b.HasOne("ERPCore.Domain.Entities.User", "CashierUser")
@@ -7025,6 +7250,13 @@ namespace ERPCore.Migrations
             modelBuilder.Entity("ERPCore.Domain.Entities.Grn", b =>
                 {
                     b.Navigation("Lines");
+
+                    b.Navigation("Payments");
+                });
+
+            modelBuilder.Entity("ERPCore.Domain.Entities.GrnLine", b =>
+                {
+                    b.Navigation("WarrantyNumbers");
                 });
 
             modelBuilder.Entity("ERPCore.Domain.Entities.GrnLine", b =>
@@ -7111,6 +7343,11 @@ namespace ERPCore.Migrations
                     b.Navigation("Lines");
                 });
 
+            modelBuilder.Entity("ERPCore.Domain.Entities.SalesReturn", b =>
+                {
+                    b.Navigation("Lines");
+                });
+
             modelBuilder.Entity("ERPCore.Domain.Entities.SalesSlip", b =>
                 {
                     b.Navigation("Lines");

Backend/ERPCore/Program.cs

@@ -103,6 +103,7 @@ builder.Services.AddScoped<IItemMeasure, ItemMeasure>();
 builder.Services.AddScoped<IFifoCostingService, FifoCostingService>();
 builder.Services.AddScoped<IStockService, StockService>();
 builder.Services.AddScoped<IGrnService, GrnService>();
+builder.Services.AddScoped<IGrnPaymentService, GrnPaymentService>();
 
 // Sales (Phase 1)
 builder.Services.AddScoped<ISalesPricingService, SalesPricingService>();

Backend/ERPCore/Services/GeneralLedgerService.cs

@@ -1,11 +1,21 @@
+using System.Text;
+using System.Text.Json;
 using ERPCore.Infra.Gl;
+using ERPCore.Services.Gl;
 using ERPCore.Services.Interfaces;
+using ERPCore.System.Errors;
 
 namespace ERPCore.Services;
 
 /// <inheritdoc cref="IGeneralLedgerService"/>
 public sealed class GeneralLedgerService : IGeneralLedgerService
 {
+    private static readonly JsonSerializerOptions JsonOptions = new()
+    {
+        PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
+        PropertyNameCaseInsensitive = true
+    };
+
     private readonly IGeneralLedgerClient _client;
 
     public GeneralLedgerService(IGeneralLedgerClient client) => _client = client;
@@ -13,4 +23,89 @@ public sealed class GeneralLedgerService : IGeneralLedgerService
     public Task<GeneralLedgerResponse> ForwardAsync(
         HttpMethod method, string path, string? queryString, string? contentType, Stream? body, CancellationToken ct)
         => _client.SendAsync(method, path, queryString, contentType, body, ct);
+
+    public async Task<GlJournalEntryResult> PostJournalEntryAsync(GlJournalEntryRequest request, CancellationToken ct)
+    {
+        using var body = new MemoryStream(JsonSerializer.SerializeToUtf8Bytes(request, JsonOptions));
+        var response = await _client.SendAsync(HttpMethod.Post, "journal-entries", null, "application/json", body, ct);
+        var data = ParseSuccess<GlJournalEntryData>(response);
+        return new GlJournalEntryResult(data.JournalNo, data.IsPosted);
+    }
+
+    public async Task<GlPeriod> GetPeriodByDateAsync(DateOnly date, CancellationToken ct)
+    {
+        var response = await _client.SendAsync(
+            HttpMethod.Get, "fiscal-years/periods/by-date", $"?date={date:yyyy-MM-dd}", null, null, ct);
+        var data = ParseSuccess<GlPeriodData>(response);
+        return new GlPeriod(data.PeriodId, data.FiscalYearId);
+    }
+
+    public async Task<IReadOnlyList<GlBankAccount>> ListBankAccountsAsync(CancellationToken ct)
+    {
+        var response = await _client.SendAsync(HttpMethod.Get, "bank-accounts", "?accountType=Both", null, null, ct);
+        var data = ParseSuccess<List<GlBankAccountData>>(response);
+        return data.Select(a => new GlBankAccount(
+            a.AccountType, a.AccountId, a.AccountName, a.BankName,
+            a.CashAccountTypeName, a.AccountNumber, a.GlAccountId, a.GlAccountCode, a.CurrencyCode)).ToList();
+    }
+
+    /// <summary>
+    /// Parses GL's <c>ApiResponse</c> envelope (case-insensitively, since GL's success bodies are
+    /// camelCase and its error bodies are PascalCase — docs/12 §4) and throws
+    /// <see cref="DomainException"/> if the call didn't succeed.
+    /// </summary>
+    private static T ParseSuccess<T>(GeneralLedgerResponse response)
+    {
+        GlEnvelope<T>? envelope;
+        try
+        {
+            envelope = JsonSerializer.Deserialize<GlEnvelope<T>>(response.Body, JsonOptions);
+        }
+        catch (JsonException)
+        {
+            envelope = null;
+        }
+
+        if (response.StatusCode is < 200 or >= 300 || envelope is null || !envelope.Success || envelope.Data is null)
+        {
+            var message = envelope?.Message ?? "The General Ledger service rejected the request.";
+            var status = response.StatusCode is >= 400 and < 500 ? response.StatusCode : 502;
+            throw new DomainException(ErrorCodes.GlRequestFailed, message, status);
+        }
+
+        return envelope.Data;
+    }
+
+    private sealed class GlEnvelope<T>
+    {
+        public int StatusCode { get; set; }
+        public bool Success { get; set; }
+        public string? Message { get; set; }
+        public T? Data { get; set; }
+    }
+
+    private sealed class GlJournalEntryData
+    {
+        public string JournalNo { get; set; } = string.Empty;
+        public bool IsPosted { get; set; }
+    }
+
+    private sealed class GlPeriodData
+    {
+        public int PeriodId { get; set; }
+        public int FiscalYearId { get; set; }
+    }
+
+    private sealed class GlBankAccountData
+    {
+        public string AccountType { get; set; } = string.Empty;
+        public long AccountId { get; set; }
+        public string AccountName { get; set; } = string.Empty;
+        public string? BankName { get; set; }
+        public string? CashAccountTypeName { get; set; }
+        public string? AccountNumber { get; set; }
+        public long GlAccountId { get; set; }
+        public string GlAccountCode { get; set; } = string.Empty;
+        public string CurrencyCode { get; set; } = string.Empty;
+    }
 }

Backend/ERPCore/Services/Gl/GlModels.cs

@@ -0,0 +1,27 @@
+namespace ERPCore.Services.Gl;
+
+/// <summary>
+/// Purpose-built request/response shapes for the specific GL endpoints ERPCore's GRN
+/// module calls directly (journal-entries, period lookup, bank-account listing) — not
+/// a full model of GL's contract (docs/12-GENERAL-LEDGER-INTEGRATION.md §5/§6: typed
+/// DTOs are added only for the flow that actually needs them).
+/// </summary>
+public sealed record GlJournalEntryLineRequest(string AccountCode, decimal DebitAmount, decimal CreditAmount, string? Memo = null);
+
+public sealed class GlJournalEntryRequest
+{
+    public int PeriodId { get; set; }
+    public DateOnly EntryDate { get; set; }
+    public string? SourceModule { get; set; }
+    public string? Reference { get; set; }
+    public string? Narration { get; set; }
+    public List<GlJournalEntryLineRequest> Lines { get; set; } = new();
+}
+
+public sealed record GlJournalEntryResult(string JournalNo, bool IsPosted);
+
+public sealed record GlPeriod(int PeriodId, int FiscalYearId);
+
+public sealed record GlBankAccount(
+    string AccountType, long AccountId, string AccountName, string? BankName,
+    string? CashAccountTypeName, string? AccountNumber, long GlAccountId, string GlAccountCode, string CurrencyCode);

Backend/ERPCore/Services/GrnPaymentService.cs

@@ -0,0 +1,120 @@
+using ERPCore.Domain.Entities;
+using ERPCore.Domain.Enums;
+using ERPCore.Dtos.Grn;
+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;
+
+/// <summary>
+/// Vendor payments against a confirmed GRN. Multiple installments are allowed until
+/// <see cref="Grn.BalanceAmount"/> reaches zero. Each payment posts its own real GL
+/// journal entry (Debit GRN Clearing / Credit the selected bank-or-cash account) before
+/// being recorded, using the same call-GL-before-commit pattern as <see cref="GrnService.ConfirmAsync"/>
+/// so a rejected/unreachable GL post rolls back the whole payment atomically.
+/// </summary>
+public sealed class GrnPaymentService : IGrnPaymentService
+{
+    private readonly IRepository<Grn> _grns;
+    private readonly IRepository<GrnPayment> _payments;
+    private readonly IGeneralLedgerService _gl;
+    private readonly ICurrentUser _currentUser;
+    private readonly IUnitOfWork _uow;
+    private readonly string _glClearingAccountCode;
+
+    public GrnPaymentService(
+        IRepository<Grn> grns, IRepository<GrnPayment> payments, IGeneralLedgerService gl,
+        ICurrentUser currentUser, IUnitOfWork uow, IConfiguration configuration)
+    {
+        _grns = grns;
+        _payments = payments;
+        _gl = gl;
+        _currentUser = currentUser;
+        _uow = uow;
+        _glClearingAccountCode = configuration["Grn:GlClearingAccountCode"] ?? string.Empty;
+    }
+
+    public async Task<GrnPaymentDto> PayAsync(int grnId, CreateGrnPaymentRequest request, CancellationToken ct = default)
+    {
+        var grn = await _grns.Query().FirstOrDefaultAsync(g => g.GrnId == grnId, ct)
+            ?? throw new NotFoundException($"GRN {grnId} was not found.");
+
+        if (grn.Status == GrnStatus.Draft)
+            throw new DomainException(ErrorCodes.GrnNotPayable, $"GRN {grnId} must be confirmed before it can be paid.", 409);
+        if (request.Amount > grn.BalanceAmount)
+            throw new DomainException(ErrorCodes.GrnPaymentExceedsBalance,
+                $"Payment amount {request.Amount} exceeds the remaining balance {grn.BalanceAmount}.", 400);
+
+        var accounts = await _gl.ListBankAccountsAsync(ct);
+        var account = accounts.FirstOrDefault(a => a.AccountId == request.GlBankAccountId)
+            ?? throw new DomainException(ErrorCodes.GrnBankAccountNotFound, $"Bank/cash account {request.GlBankAccountId} was not found.", 404);
+
+        var actor = _currentUser.AuditUserId;
+        var now = DateTime.UtcNow;
+
+        var payment = await _uow.ExecuteInTransactionAsync(async token =>
+        {
+            // Same atomicity approach as GrnService.ConfirmAsync: 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 period = await _gl.GetPeriodByDateAsync(DateOnly.FromDateTime(now), token);
+            var posted = await _gl.PostJournalEntryAsync(new GlJournalEntryRequest
+            {
+                PeriodId = period.PeriodId,
+                EntryDate = DateOnly.FromDateTime(now),
+                SourceModule = "GRN_PAYMENT",
+                Reference = grn.DocNo,
+                Narration = $"Payment against GRN {grn.DocNo}",
+                Lines =
+                [
+                    new GlJournalEntryLineRequest(_glClearingAccountCode, request.Amount, 0m, $"Payment against GRN {grn.DocNo}"),
+                    new GlJournalEntryLineRequest(account.GlAccountCode, 0m, request.Amount, $"Payment against GRN {grn.DocNo}")
+                ]
+            }, token);
+
+            var entity = new GrnPayment
+            {
+                GrnId = grn.GrnId,
+                Amount = request.Amount,
+                PaymentDate = now,
+                GlBankAccountId = account.AccountId,
+                BankAccountName = account.AccountName,
+                Reference = request.Reference,
+                GlJournalNo = posted.JournalNo,
+                CreatedBy = actor,
+                CreatedAt = now
+            };
+            await _payments.AddAsync(entity, token);
+
+            grn.PaidAmount += request.Amount;
+            grn.BalanceAmount -= request.Amount;
+
+            return entity;
+        }, ct);
+
+        return Map(payment);
+    }
+
+    public async Task<IReadOnlyList<GrnPaymentDto>> ListAsync(int grnId, CancellationToken ct = default)
+    {
+        if (!await _grns.Query().AnyAsync(g => g.GrnId == grnId, ct))
+            throw new NotFoundException($"GRN {grnId} was not found.");
+
+        return await _payments.Query().AsNoTracking()
+            .Where(p => p.GrnId == grnId)
+            .OrderByDescending(p => p.GrnPaymentId)
+            .Select(p => new GrnPaymentDto(
+                p.GrnPaymentId, p.GrnId, p.Amount, p.PaymentDate,
+                p.GlBankAccountId, p.BankAccountName, p.Reference, p.GlJournalNo, p.CreatedAt))
+            .ToListAsync(ct);
+    }
+
+    private static GrnPaymentDto Map(GrnPayment p) => new(
+        p.GrnPaymentId, p.GrnId, p.Amount, p.PaymentDate,
+        p.GlBankAccountId, p.BankAccountName, p.Reference, p.GlJournalNo, p.CreatedAt);
+}

Backend/ERPCore/Services/GrnService.cs

@@ -6,6 +6,7 @@ using ERPCore.Dtos.Grn;
 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;
@@ -38,13 +39,18 @@ public sealed class GrnService : IGrnService
     private readonly INumberSequenceService _numbers;
     private readonly ICurrentUser _currentUser;
     private readonly IUnitOfWork _uow;
+    private readonly IGeneralLedgerService _gl;
+    private readonly string _glInventoryAccountCode;
+    private readonly string _glVatRecoverableAccountCode;
+    private readonly string _glClearingAccountCode;
 
     public GrnService(
         IRepository<Grn> grns, IRepository<PurchaseOrder> pos, IRepository<PoLine> poLines,
         IRepository<Item> items, IRepository<Warehouse> warehouses,
         IRepository<Bin> bins, IRepository<Vendor> vendors, IRepository<Batch> batches,
         IRepository<StockLayer> layers, IRepository<StockLedger> ledger,
-        IFifoCostingService fifo, INumberSequenceService numbers, ICurrentUser currentUser, IUnitOfWork uow)
+        IFifoCostingService fifo, INumberSequenceService numbers, ICurrentUser currentUser, IUnitOfWork uow,
+        IGeneralLedgerService gl, IConfiguration configuration)
     {
         _grns = grns;
         _pos = pos;
@@ -60,6 +66,10 @@ public sealed class GrnService : IGrnService
         _numbers = numbers;
         _currentUser = currentUser;
         _uow = uow;
+        _gl = gl;
+        _glInventoryAccountCode = configuration["Grn:GlInventoryAccountCode"] ?? string.Empty;
+        _glVatRecoverableAccountCode = configuration["Grn:GlVatRecoverableAccountCode"] ?? string.Empty;
+        _glClearingAccountCode = configuration["Grn:GlClearingAccountCode"] ?? string.Empty;
     }
 
     public async Task<PagedResponse<GrnSummaryDto>> ListAsync(
@@ -82,7 +92,7 @@ public sealed class GrnService : IGrnService
             .Skip(query.Skip).Take(query.PageSize)
             .Select(g => new GrnSummaryDto(
                 g.GrnId, g.DocNo, g.PoId, g.VendorId, g.WarehouseId, g.Status,
-                g.CreatedBy, g.CreatedAt, g.PostedAt, g.Lines.Count))
+                g.CreatedBy, g.CreatedAt, g.PostedAt, g.Lines.Count, g.PaidAmount, g.BalanceAmount))
             .ToListAsync(ct);
 
         return PagedResponse<GrnSummaryDto>.Create(rows, query.Page, query.PageSize, total);
@@ -260,15 +270,47 @@ public sealed class GrnService : IGrnService
                 }
             }
 
+            // Post the real GL journal entry for this receipt before committing — if GL
+            // rejects it or is unreachable, the exception propagates out of this callback
+            // and the whole transaction (FIFO layers, stock ledger, PO accrual) rolls back
+            // 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 period = await _gl.GetPeriodByDateAsync(DateOnly.FromDateTime(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}"));
+                if (line.VatAmount > 0)
+                    glLines.Add(new GlJournalEntryLineRequest(_glVatRecoverableAccountCode, line.VatAmount, 0m, $"GRN {grn.DocNo} line {line.GrnLineId} VAT"));
+                totalPayable += line.LineTotal;
+            }
+            glLines.Add(new GlJournalEntryLineRequest(_glClearingAccountCode, 0m, totalPayable, $"GRN {grn.DocNo} received"));
+
+            var posted = await _gl.PostJournalEntryAsync(new GlJournalEntryRequest
+            {
+                PeriodId = period.PeriodId,
+                EntryDate = DateOnly.FromDateTime(now),
+                SourceModule = "GRN",
+                Reference = grn.DocNo,
+                Narration = $"Goods received - GRN {grn.DocNo}",
+                Lines = glLines
+            }, token);
+
             grn.Status = GrnStatus.Confirmed;
             grn.PostedAt = now;
+            grn.GlJournalNo = posted.JournalNo;
+            grn.GlPostedAt = now;
+            grn.PaidAmount = 0m;
+            grn.BalanceAmount = totalPayable;
 
             await UpdatePoStatusAsync(grn.PoId, token);
             return 0;
         }, ct);
 
         return new GrnConfirmResultDto(
-            grn.GrnId, grn.Status, now,
+            grn.GrnId, grn.Status, now, grn.GlJournalNo ?? string.Empty, grn.BalanceAmount,
             createdLayers.Select(ToCreatedLayer).ToList(),
             ledgerRefs.Select(l => l.LedgerId).ToList(),
             await GetPoStatusAsync(grn.PoId, ct));
@@ -395,7 +437,7 @@ public sealed class GrnService : IGrnService
             .Select(l => l.LedgerId).ToListAsync(ct);
 
         return new GrnConfirmResultDto(
-            grn.GrnId, grn.Status, grn.PostedAt ?? grn.CreatedAt,
+            grn.GrnId, grn.Status, grn.PostedAt ?? grn.CreatedAt, grn.GlJournalNo ?? string.Empty, grn.BalanceAmount,
             layers.Select(ToCreatedLayer).ToList(), ledgerRefs, await GetPoStatusAsync(grn.PoId, ct));
     }
 
@@ -404,6 +446,7 @@ public sealed class GrnService : IGrnService
 
     private static GrnDto Map(Grn g) => new(
         g.GrnId, g.DocNo, g.PoId, g.VendorId, g.WarehouseId, g.Status, g.CreatedBy, g.CreatedAt, g.PostedAt,
+        g.GlJournalNo, g.PaidAmount, g.BalanceAmount,
         g.Lines.OrderBy(l => l.GrnLineId).Select(l => new GrnLineDto(
             l.GrnLineId, l.PoLineId, l.ItemId, l.BinId, l.Qty, l.UnitCost, l.PoUnitPrice,
             l.DiscountPct, l.NetUnitCost, l.VatPct, l.VatAmount, l.ReceivedValue, l.LineTotal,

Backend/ERPCore/Services/Interfaces/IGeneralLedgerService.cs

@@ -1,16 +1,27 @@
 using ERPCore.Infra.Gl;
+using ERPCore.Services.Gl;
 
 namespace ERPCore.Services.Interfaces;
 
 /// <summary>
 /// Single entry point into the external General Ledger service — the one function
 /// used both by <see cref="ERPCore.Controllers.GeneralLedgerController"/> (frontend
-/// requests, forwarded verbatim) and, once wired, other ERPCore services that need to
+/// requests, forwarded verbatim) and by other ERPCore services that post directly to
-/// post directly to GL (e.g. GRN confirm, adjustments — docs/12-GENERAL-LEDGER-INTEGRATION.md).
+/// GL (docs/12-GENERAL-LEDGER-INTEGRATION.md §5/§6). <see cref="ForwardAsync"/> stays a
-/// No business logic lives here yet; this pass only connects the transport.
+/// byte-for-byte passthrough; the three typed methods below are the first internal
+/// callers (GRN receipt + payment posting) and model only what those flows need.
 /// </summary>
 public interface IGeneralLedgerService
 {
     Task<GeneralLedgerResponse> ForwardAsync(
         HttpMethod method, string path, string? queryString, string? contentType, Stream? body, CancellationToken ct);
+
+    /// <summary>Creates and posts a balanced journal entry. Throws <see cref="ERPCore.System.Errors.DomainException"/> on rejection/unreachability.</summary>
+    Task<GlJournalEntryResult> PostJournalEntryAsync(GlJournalEntryRequest request, CancellationToken ct);
+
+    /// <summary>Resolves the accounting period covering <paramref name="date"/>.</summary>
+    Task<GlPeriod> GetPeriodByDateAsync(DateOnly date, CancellationToken ct);
+
+    /// <summary>Lists GL's cash and bank accounts (default: both types).</summary>
+    Task<IReadOnlyList<GlBankAccount>> ListBankAccountsAsync(CancellationToken ct);
 }

Backend/ERPCore/Services/Interfaces/IGrnPaymentService.cs

@@ -0,0 +1,10 @@
+using ERPCore.Dtos.Grn;
+
+namespace ERPCore.Services.Interfaces;
+
+/// <summary>Vendor payments against a confirmed GRN's balance (installments allowed).</summary>
+public interface IGrnPaymentService
+{
+    Task<GrnPaymentDto> PayAsync(int grnId, CreateGrnPaymentRequest request, CancellationToken ct = default);
+    Task<IReadOnlyList<GrnPaymentDto>> ListAsync(int grnId, CancellationToken ct = default);
+}

Backend/ERPCore/System/Errors/ErrorCodes.cs

@@ -70,4 +70,11 @@ public static class ErrorCodes
 
     // General Ledger service proxy (GeneralLedgerController → external GL service, docs/12)
     public const string GlServiceUnavailable = "GL_SERVICE_UNAVAILABLE";
+    // General Ledger typed internal calls (GRN receipt/payment posting, docs/12 §5's deferred work)
+    public const string GlRequestFailed = "GL_REQUEST_FAILED";
+
+    // GRN payments
+    public const string GrnNotPayable = "GRN_NOT_PAYABLE";
+    public const string GrnPaymentExceedsBalance = "GRN_PAYMENT_EXCEEDS_BALANCE";
+    public const string GrnBankAccountNotFound = "GRN_BANK_ACCOUNT_NOT_FOUND";
 }

Backend/ERPCore/appsettings.json

@@ -26,5 +26,10 @@
     "BaseUrl": "https://localhost:7024/api/v1/",
     "ApiKey": "1A5FE0E389C029B1FBCD2A94650CEBF0656083BF06FF48E5E11987040ABA262D"
   },
+  "Grn": {
+    "GlInventoryAccountCode": "1100",
+    "GlVatRecoverableAccountCode": "1200",
+    "GlClearingAccountCode": "2000"
+  },
   "AllowedHosts": "*"
 }

Frontend/erp-system/app/dashboard/receiving/grn/[id]/page.tsx

@@ -3,7 +3,7 @@
 import { useEffect, useRef, useState } from "react"
 import { useParams } from "next/navigation"
 import Link from "next/link"
-import { CheckCircle2, PackageCheck, PackageX, ShieldAlert, XCircle } from "lucide-react"
+import { BookOpen, CheckCircle2, CircleDollarSign, PackageCheck, PackageX, ShieldAlert, XCircle } from "lucide-react"
 
 import { grnsApi } from "@/lib/api/grns"
 import { warehousesApi } from "@/lib/api/warehouses"
@@ -11,8 +11,9 @@ import { itemsApi } from "@/lib/api/items"
 import { uomsApi } from "@/lib/api/uoms"
 import { baseUomLabel } from "@/lib/uom-label"
 import { errorMessage } from "@/lib/error-map"
+import { formatAmount } from "@/lib/format"
 import { cn } from "@/lib/utils"
-import { ConfirmGrnResponse, Grn } from "@/types/grn"
+import { ConfirmGrnResponse, Grn, GrnPayment } from "@/types/grn"
 import { Bin, ItemListItem, Uom } from "@/types/master-data"
 
 import { Badge } from "@/components/ui/badge"
@@ -20,7 +21,8 @@ import { Button, buttonVariants } from "@/components/ui/button"
 import { Skeleton } from "@/components/ui/skeleton"
 import { Table, TableBody, TableCell, TableHead, TableHeader, TableRow } from "@/components/ui/table"
 import { toast } from "@/components/ui/toast"
-import { GrnStatusBadge, HoldStatusBadge } from "@/components/receiving/status-badges"
+import { GrnPaymentStatusBadge, GrnStatusBadge, HoldStatusBadge } from "@/components/receiving/status-badges"
+import { GrnPaymentDialog } from "@/components/receiving/GrnPaymentDialog"
 
 export default function GrnDetailPage() {
   const params = useParams<{ id: string }>()
@@ -36,6 +38,9 @@ export default function GrnDetailPage() {
   const [confirmResult, setConfirmResult] = useState<ConfirmGrnResponse | null>(null)
   const [releasingLineId, setReleasingLineId] = useState<number | null>(null)
 
+  const [payments, setPayments] = useState<GrnPayment[]>([])
+  const [payDialogOpen, setPayDialogOpen] = useState(false)
+
   // Stable per detail-page-session key so a retried confirm click doesn't double-post.
   const idempotencyKey = useRef(crypto.randomUUID())
 
@@ -55,6 +60,18 @@ export default function GrnDetailPage() {
     warehousesApi.listBins(grn.warehouseId).then(setBins).catch(() => setBins([]))
   }, [grn?.warehouseId])
 
+  useEffect(() => {
+    if (!grn || grn.status === "Draft") return
+    grnsApi.listPayments(grn.grnId).then(setPayments).catch(() => setPayments([]))
+  }, [grn?.grnId, grn?.status])
+
+  function handlePaid(_updated: Grn, payment: GrnPayment) {
+    setGrn((prev) =>
+      prev ? { ...prev, paidAmount: prev.paidAmount + payment.amount, balanceAmount: prev.balanceAmount - payment.amount } : prev
+    )
+    setPayments((prev) => [payment, ...prev])
+  }
+
   function itemFor(itemId: number) {
     return items.find((i) => i.itemId === itemId)
   }
@@ -70,8 +87,10 @@ export default function GrnDetailPage() {
     try {
       const result = await grnsApi.confirm(grn.grnId, idempotencyKey.current)
       setConfirmResult(result)
-      setGrn((prev) => (prev ? { ...prev, status: result.status } : prev))
+      setGrn((prev) =>
-      toast.success("GRN confirmed", `${result.createdLayers.length} layer(s) posted to stock.`)
+        prev ? { ...prev, status: result.status, glJournalNo: result.glJournalNo, balanceAmount: result.balanceAmount } : prev
+      )
+      toast.success("GRN confirmed", `${result.createdLayers.length} layer(s) posted to stock. Journal ${result.glJournalNo}.`)
     } catch (err) {
       setError(errorMessage(err))
       toast.error("Could not confirm GRN", errorMessage(err))
@@ -121,6 +140,7 @@ export default function GrnDetailPage() {
             <div className="flex items-center gap-3">
               <h1 className="text-2xl font-bold text-foreground">{grn.docNo}</h1>
               <GrnStatusBadge status={grn.status} />
+              {grn.status !== "Draft" && <GrnPaymentStatusBadge paidAmount={grn.paidAmount} balanceAmount={grn.balanceAmount} />}
             </div>
             <p className="text-base text-muted-foreground">
               {grn.poId ? `Against PO #${grn.poId}` : "Direct receipt"} — Vendor #{grn.vendorId} — Warehouse #{grn.warehouseId}
@@ -128,14 +148,36 @@ export default function GrnDetailPage() {
           </div>
         </div>
 
-        {grn.status === "Draft" && (
+        <div className="flex items-center gap-2">
-          <Button size="lg" onClick={handleConfirm} disabled={confirming}>
+          {grn.status !== "Draft" && (
-            <PackageCheck className="size-5" />
+            <>
-            {confirming ? "Confirming…" : "Confirm GRN"}
+              <Link
-          </Button>
+                href="/dashboard/ledgers/general-ledger"
-        )}
+                className={cn(buttonVariants({ variant: "outline", size: "lg" }))}
+                title="View this GRN's postings in the General Ledger report"
+              >
+                <BookOpen className="size-5" />
+                View in Ledger
+              </Link>
+              {grn.balanceAmount > 0 && (
+                <Button size="lg" onClick={() => setPayDialogOpen(true)}>
+                  <CircleDollarSign className="size-5" />
+                  Pay
+                </Button>
+              )}
+            </>
+          )}
+          {grn.status === "Draft" && (
+            <Button size="lg" onClick={handleConfirm} disabled={confirming}>
+              <PackageCheck className="size-5" />
+              {confirming ? "Confirming…" : "Confirm GRN"}
+            </Button>
+          )}
+        </div>
       </div>
 
+      <GrnPaymentDialog grn={grn} open={payDialogOpen} onOpenChange={setPayDialogOpen} onPaid={handlePaid} />
+
       {error && (
         <div className="rounded-lg border border-destructive/30 bg-destructive/5 p-5 text-base text-destructive">{error}</div>
       )}
@@ -150,6 +192,7 @@ export default function GrnDetailPage() {
             Layers: {confirmResult.createdLayers.map((l) => `#${l.layerId} (${l.qtyReceived} @ ${l.unitCost})`).join(", ")}
           </div>
           <div className="text-sm text-muted-foreground">Ledger refs: {confirmResult.ledgerRefs.join(", ")}</div>
+          <div className="text-sm text-muted-foreground">GL journal entry: {confirmResult.glJournalNo}</div>
           {confirmResult.poStatus && <div className="text-sm text-muted-foreground">PO status: {confirmResult.poStatus}</div>}
         </div>
       )}
@@ -258,7 +301,7 @@ export default function GrnDetailPage() {
       </Table>
       </div>
 
-      <div className="flex justify-end gap-8 border-t border-border pt-4 text-base">
+      <div className="flex flex-wrap justify-end gap-8 border-t border-border pt-4 text-base">
         <div className="flex gap-3">
           <span className="text-muted-foreground">Stock value (excl. VAT)</span>
           <span className="tabular-nums">{grn.lines.reduce((s, l) => s + l.receivedValue, 0).toFixed(2)}</span>
@@ -271,7 +314,49 @@ export default function GrnDetailPage() {
           <span className="text-muted-foreground">Document total</span>
           <span className="font-semibold tabular-nums">{grn.lines.reduce((s, l) => s + l.lineTotal, 0).toFixed(2)}</span>
         </div>
+        {grn.status !== "Draft" && (
+          <>
+            <div className="flex gap-3">
+              <span className="text-muted-foreground">Amount paid</span>
+              <span className="tabular-nums">{formatAmount(grn.paidAmount)}</span>
+            </div>
+            <div className="flex gap-3">
+              <span className="text-muted-foreground">Balance due</span>
+              <span className="font-semibold tabular-nums">{formatAmount(grn.balanceAmount)}</span>
+            </div>
+          </>
+        )}
       </div>
+
+      {grn.status !== "Draft" && payments.length > 0 && (
+        <div className="flex flex-col gap-3">
+          <h2 className="text-lg font-semibold text-foreground">Payment History</h2>
+          <div className="overflow-x-auto">
+            <Table className="text-base">
+              <TableHeader>
+                <TableRow>
+                  <TableHead className="h-12 px-3 text-sm">Date</TableHead>
+                  <TableHead className="h-12 px-3 text-sm text-right">Amount</TableHead>
+                  <TableHead className="h-12 px-3 text-sm">Account</TableHead>
+                  <TableHead className="h-12 px-3 text-sm">Reference</TableHead>
+                  <TableHead className="h-12 px-3 text-sm">GL Journal</TableHead>
+                </TableRow>
+              </TableHeader>
+              <TableBody>
+                {payments.map((p) => (
+                  <TableRow key={p.grnPaymentId}>
+                    <TableCell className="px-3 py-3.5">{new Date(p.paymentDate).toLocaleString()}</TableCell>
+                    <TableCell className="px-3 py-3.5 text-right tabular-nums">{formatAmount(p.amount)}</TableCell>
+                    <TableCell className="px-3 py-3.5">{p.bankAccountName}</TableCell>
+                    <TableCell className="px-3 py-3.5">{p.reference ?? "—"}</TableCell>
+                    <TableCell className="px-3 py-3.5">{p.glJournalNo ?? "—"}</TableCell>
+                  </TableRow>
+                ))}
+              </TableBody>
+            </Table>
+          </div>
+        </div>
+      )}
     </div>
   )
 }

Frontend/erp-system/app/dashboard/receiving/grn/page.tsx

@@ -6,6 +6,7 @@ import { ChevronLeft, ChevronRight, Eye, PackageSearch, Plus, Search } from "luc
 
 import { grnsApi } from "@/lib/api/grns"
 import { errorMessage } from "@/lib/error-map"
+import { formatAmount } from "@/lib/format"
 import { GrnStatus, GrnSummary } from "@/types/grn"
 import { PaginationMeta } from "@/types/common"
 import { cn } from "@/lib/utils"
@@ -22,7 +23,7 @@ import {
   TableHeader,
   TableRow,
 } from "@/components/ui/table"
-import { GrnStatusBadge } from "@/components/receiving/status-badges"
+import { GrnPaymentStatusBadge, GrnStatusBadge } from "@/components/receiving/status-badges"
 
 type StatusFilter = GrnStatus | "All"
 
@@ -174,6 +175,8 @@ export default function GrnListPage() {
                 <TableHead className="h-12 px-3 text-sm">Vendor</TableHead>
                 <TableHead className="h-12 px-3 text-sm">Warehouse</TableHead>
                 <TableHead className="h-12 px-3 text-sm">Status</TableHead>
+                <TableHead className="h-12 px-3 text-sm text-right">Balance</TableHead>
+                <TableHead className="h-12 px-3 text-sm">Payment</TableHead>
                 <TableHead className="h-12 px-3 text-sm">Created</TableHead>
                 <TableHead className="h-12 px-3 text-sm">Actions</TableHead>
               </TableRow>
@@ -196,6 +199,16 @@ export default function GrnListPage() {
                     <TableCell className="px-3 py-3.5">
                       <GrnStatusBadge status={grn.status} />
                     </TableCell>
+                    <TableCell className="px-3 py-3.5 text-right tabular-nums">
+                      {grn.status === "Draft" ? "—" : formatAmount(grn.balanceAmount)}
+                    </TableCell>
+                    <TableCell className="px-3 py-3.5">
+                      {grn.status === "Draft" ? (
+                        <span className="text-sm text-muted-foreground">—</span>
+                      ) : (
+                        <GrnPaymentStatusBadge paidAmount={grn.paidAmount} balanceAmount={grn.balanceAmount} />
+                      )}
+                    </TableCell>
                     <TableCell className="px-3 py-3.5">{new Date(grn.createdAt).toLocaleString()}</TableCell>
                     <TableCell className="px-3 py-3.5">
                       <div className="flex items-center gap-1">

Frontend/erp-system/components/receiving/GrnPaymentDialog.tsx

@@ -0,0 +1,145 @@
+"use client"
+
+import { useEffect, useState } from "react"
+
+import { bankAccountsApi } from "@/lib/api/general-ledger"
+import { grnsApi } from "@/lib/api/grns"
+import { errorMessage } from "@/lib/error-map"
+import { formatAmount } from "@/lib/format"
+import { CashAndBankAccountDto } from "@/types/general-ledger"
+import { Grn, GrnPayment } from "@/types/grn"
+
+import { Button } from "@/components/ui/button"
+import { Dialog, DialogContent, DialogFooter, DialogHeader, DialogTitle } from "@/components/ui/dialog"
+import { Field, FieldError, FieldGroup, FieldLabel } from "@/components/ui/field"
+import { Input } from "@/components/ui/input"
+import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from "@/components/ui/select"
+import { toast } from "@/components/ui/toast"
+
+interface GrnPaymentDialogProps {
+  grn: Grn | null
+  open: boolean
+  onOpenChange: (open: boolean) => void
+  onPaid: (grn: Grn, payment: GrnPayment) => void
+}
+
+/** Pay the vendor against a confirmed GRN's balance — full or partial, from an existing
+ * GL cash/bank account. Modeled on ReceivedChequeDialog's "pick an account, submit" shape. */
+export function GrnPaymentDialog({ grn, open, onOpenChange, onPaid }: GrnPaymentDialogProps) {
+  const [accounts, setAccounts] = useState<CashAndBankAccountDto[] | null>(null)
+  const [glBankAccountId, setGlBankAccountId] = useState("")
+  const [amount, setAmount] = useState("")
+  const [reference, setReference] = useState("")
+  const [errors, setErrors] = useState<Record<string, string>>({})
+  const [submitting, setSubmitting] = useState(false)
+
+  // Reset the form fields for a fresh open (or a different GRN) during render, React's own
+  // sanctioned "adjust state while rendering" pattern (see the General Ledger report page's
+  // periodKey comment) — not inside the effect below, which would be a synchronous
+  // setState-in-effect (react-hooks/set-state-in-effect).
+  const openKey = open && grn ? `${grn.grnId}` : null
+  const [resetFor, setResetFor] = useState<string | null>(null)
+  if (openKey !== null && resetFor !== openKey) {
+    setResetFor(openKey)
+    setAmount(grn!.balanceAmount.toFixed(2))
+    setGlBankAccountId("")
+    setReference("")
+    setErrors({})
+  }
+
+  useEffect(() => {
+    if (!open || accounts !== null) return
+    bankAccountsApi.list("Both").then(setAccounts).catch(() => setAccounts([]))
+  }, [open, accounts])
+
+  if (!grn) return null
+
+  async function submit() {
+    if (!grn) return
+    const nextErrors: Record<string, string> = {}
+    const amountNum = Number(amount)
+    if (!glBankAccountId) nextErrors.glBankAccountId = "Select an account to pay from"
+    if (!amount || Number.isNaN(amountNum) || amountNum <= 0) nextErrors.amount = "Enter a valid amount"
+    else if (amountNum > grn.balanceAmount) nextErrors.amount = `Cannot exceed the balance (${formatAmount(grn.balanceAmount)})`
+    setErrors(nextErrors)
+    if (Object.keys(nextErrors).length > 0) return
+
+    setSubmitting(true)
+    try {
+      const payment = await grnsApi.pay(grn.grnId, {
+        amount: amountNum,
+        glBankAccountId: Number(glBankAccountId),
+        reference: reference || undefined,
+      })
+      toast.success("Payment recorded", `${formatAmount(amountNum)} posted to the ledger (${payment.glJournalNo ?? "—"}).`)
+      onPaid(grn, payment)
+      onOpenChange(false)
+    } catch (err) {
+      toast.error("Could not record payment", errorMessage(err))
+    } finally {
+      setSubmitting(false)
+    }
+  }
+
+  return (
+    <Dialog open={open} onOpenChange={onOpenChange}>
+      <DialogContent className="sm:max-w-md">
+        <DialogHeader>
+          <DialogTitle>Pay GRN {grn.docNo}</DialogTitle>
+        </DialogHeader>
+
+        <p className="text-sm text-muted-foreground">
+          Balance due: <span className="font-medium text-foreground tabular-nums">{formatAmount(grn.balanceAmount)}</span>
+        </p>
+
+        <FieldGroup>
+          <Field data-invalid={!!errors.glBankAccountId}>
+            <FieldLabel htmlFor="grn-pay-account">Pay from</FieldLabel>
+            <Select<string> value={glBankAccountId} onValueChange={(v) => setGlBankAccountId(v ?? "")}>
+              <SelectTrigger id="grn-pay-account" className="w-full text-base" aria-invalid={!!errors.glBankAccountId}>
+                <SelectValue placeholder={accounts === null ? "Loading…" : "Select a cash/bank account"} />
+              </SelectTrigger>
+              <SelectContent>
+                {(accounts ?? []).map((a) => (
+                  <SelectItem key={a.accountId} value={String(a.accountId)} label={a.accountName} className="text-base">
+                    {a.accountName} ({a.accountType})
+                  </SelectItem>
+                ))}
+              </SelectContent>
+            </Select>
+            <FieldError errors={[errors.glBankAccountId ? { message: errors.glBankAccountId } : undefined]} />
+          </Field>
+
+          <Field data-invalid={!!errors.amount}>
+            <FieldLabel htmlFor="grn-pay-amount">Amount</FieldLabel>
+            <Input
+              id="grn-pay-amount"
+              type="number"
+              step="0.01"
+              min="0.01"
+              max={grn.balanceAmount}
+              value={amount}
+              onChange={(e) => setAmount(e.target.value)}
+              aria-invalid={!!errors.amount}
+            />
+            <FieldError errors={[errors.amount ? { message: errors.amount } : undefined]} />
+          </Field>
+
+          <Field>
+            <FieldLabel htmlFor="grn-pay-reference">Reference (optional)</FieldLabel>
+            <Input id="grn-pay-reference" value={reference} onChange={(e) => setReference(e.target.value)} />
+          </Field>
+        </FieldGroup>
+
+        <DialogFooter>
+          <Button variant="outline" onClick={() => onOpenChange(false)} disabled={submitting}>
+            Cancel
+          </Button>
+          <Button onClick={submit} disabled={submitting}>
+            {submitting ? "Recording…" : "Record payment"}
+          </Button>
+        </DialogFooter>
+      </DialogContent>
+    </Dialog>
+  )
+}

Frontend/erp-system/components/receiving/status-badges.tsx

@@ -32,3 +32,32 @@ export function HoldStatusBadge({ status }: { status: HoldStatus }) {
     </Badge>
   )
 }
+
+export type GrnPaymentStatus = "Unpaid" | "PartiallyPaid" | "Paid"
+
+export function grnPaymentStatus(paidAmount: number, balanceAmount: number): GrnPaymentStatus {
+  if (balanceAmount <= 0) return "Paid"
+  if (paidAmount > 0) return "PartiallyPaid"
+  return "Unpaid"
+}
+
+function paymentClass(status: GrnPaymentStatus) {
+  if (status === "Paid") return "bg-success/10 text-success border-transparent"
+  if (status === "PartiallyPaid") return "bg-warning/10 text-warning border-transparent"
+  return "bg-muted text-muted-foreground border-transparent" // Unpaid
+}
+
+const paymentLabel: Record<GrnPaymentStatus, string> = {
+  Unpaid: "Unpaid",
+  PartiallyPaid: "Partial",
+  Paid: "Paid",
+}
+
+export function GrnPaymentStatusBadge({ paidAmount, balanceAmount }: { paidAmount: number; balanceAmount: number }) {
+  const status = grnPaymentStatus(paidAmount, balanceAmount)
+  return (
+    <Badge variant="outline" className={`${badgeSize} ${paymentClass(status)}`}>
+      {paymentLabel[status]}
+    </Badge>
+  )
+}

Frontend/erp-system/lib/api/grns.ts

@@ -10,8 +10,10 @@ import { apiRequest, buildQuery } from "@/lib/api-client"
 import { PagedResponse } from "@/types/common"
 import {
   ConfirmGrnResponse,
+  CreateGrnPaymentRequest,
   CreateGrnRequest,
   Grn,
+  GrnPayment,
   GrnStatus,
   GrnSummary,
   ReleaseAction,
@@ -58,4 +60,14 @@ export const grnsApi = {
       body: { action },
     })
   },
+
+  /** Pay the vendor against the GRN's balance, in full or in installments. Posts a real GL journal entry. */
+  pay(grnId: number, request: CreateGrnPaymentRequest): Promise<GrnPayment> {
+    return apiRequest<GrnPayment>(`/grns/${grnId}/payments`, { method: "POST", body: request })
+  },
+
+  /** Payment history for a GRN, newest first. */
+  listPayments(grnId: number): Promise<GrnPayment[]> {
+    return apiRequest<GrnPayment[]>(`/grns/${grnId}/payments`)
+  },
 }

Frontend/erp-system/types/general-ledger.ts

@@ -288,6 +288,8 @@ export interface CashAndBankAccountDto {
   cashAccountTypeName: string | null
   accountNumber: string | null
   glAccountId: number
+  /** The underlying GL account's business code (added GL Phase 38, 2026-08-12). */
+  glAccountCode: string
   currencyCode: string
   createdAt: string
 }

Frontend/erp-system/types/grn.ts

@@ -100,6 +100,10 @@ export interface Grn {
   createdBy: number
   createdAt: string
   postedAt: string | null
+  /** Journal number of the real GL journal entry posted for this GRN's receipt (set on confirm). */
+  glJournalNo: string | null
+  paidAmount: number
+  balanceAmount: number
   lines: GrnLine[]
 }
 
@@ -114,6 +118,8 @@ export interface GrnSummary {
   createdAt: string
   postedAt: string | null
   lineCount: number
+  paidAmount: number
+  balanceAmount: number
 }
 
 /** docs/11 §4.2 confirm response. */
@@ -132,6 +138,8 @@ export interface ConfirmGrnResponse {
   grnId: number
   status: GrnStatus
   postedAt: string
+  glJournalNo: string
+  balanceAmount: number
   createdLayers: CreatedLayer[]
   ledgerRefs: number[]
   poStatus: PurchaseOrderStatus | null
@@ -147,3 +155,23 @@ export interface ReleaseGrnLineResponse {
   grnLineId: number
   holdStatus: HoldStatus
 }
+
+/** A vendor payment against a confirmed GRN's balance (installments allowed). */
+export interface GrnPayment {
+  grnPaymentId: number
+  grnId: number
+  amount: number
+  paymentDate: string
+  glBankAccountId: number
+  bankAccountName: string
+  reference: string | null
+  /** Journal number of the real GL journal entry this payment posted. */
+  glJournalNo: string | null
+  createdAt: string
+}
+
+export interface CreateGrnPaymentRequest {
+  amount: number
+  glBankAccountId: number
+  reference?: string | null
+}