diff --git a/API/ROLAC.API.Tests/Services/ExpenseSnapshotServiceTests.cs b/API/ROLAC.API.Tests/Services/ExpenseSnapshotServiceTests.cs
new file mode 100644
index 0000000..d8918b7
--- /dev/null
+++ b/API/ROLAC.API.Tests/Services/ExpenseSnapshotServiceTests.cs
@@ -0,0 +1,141 @@
+using System.Security.Claims;
+using Microsoft.AspNetCore.Http;
+using Microsoft.EntityFrameworkCore;
+using Moq;
+using ROLAC.API.Data;
+using ROLAC.API.Data.Interceptors;
+using ROLAC.API.DTOs.Expense;
+using ROLAC.API.Entities;
+using ROLAC.API.Services;
+using ROLAC.API.Services.Logging;
+using Xunit;
+
+namespace ROLAC.API.Tests.Services;
+
+public class ExpenseSnapshotServiceTests
+{
+    private static AppDbContext BuildDb(string userId)
+    {
+        var claims = new[] { new Claim(ClaimTypes.NameIdentifier, userId) };
+        var ctx    = new DefaultHttpContext { User = new(new ClaimsIdentity(claims)) };
+        var mock   = new Mock<IHttpContextAccessor>();
+        mock.Setup(x => x.HttpContext).Returns(ctx);
+        return new AppDbContext(new DbContextOptionsBuilder<AppDbContext>()
+            .UseInMemoryDatabase(Guid.NewGuid().ToString())
+            .AddInterceptors(new AuditSaveChangesInterceptor(new CurrentUserAccessor(mock.Object))).Options);
+    }
+
+    private static (ExpenseSnapshotService svc, AppDbContext db) Build(string userId = "u1")
+    {
+        var db = BuildDb(userId);
+        db.Ministries.Add(new Ministry { Id = 1, Name_en = "Worship", Name_zh = "敬拜" });
+        db.ExpenseCategoryGroups.Add(new ExpenseCategoryGroup { Id = 1, Name_en = "Facilities" });
+        db.ExpenseSubCategories.Add(new ExpenseSubCategory { Id = 1, GroupId = 1, Name_en = "Rent" });
+        db.SaveChanges();
+        return (new ExpenseSnapshotService(db), db);
+    }
+
+    private static CreateExpenseSnapshotRequest Rent() => new()
+    {
+        Name = "Monthly Rent", MinistryId = 1, Description = "Office rent", VendorName = "Landlord X",
+        CheckNumber = "1001",
+        Lines = { new ExpenseLineInput { CategoryGroupId = 1, SubCategoryId = 1, Amount = 1200m } },
+    };
+
+    [Fact]
+    public async Task Create_PersistsHeaderAndLines_StampsCreator()
+    {
+        var (svc, db) = Build("creator-1");
+        var id = await svc.CreateAsync(Rent());
+
+        var saved = await db.ExpenseSnapshots.FindAsync(id);
+        Assert.Equal("Monthly Rent", saved!.Name);
+        Assert.Equal("creator-1", saved.CreatedBy);
+        Assert.Equal(1, await db.ExpenseSnapshotLines.CountAsync(l => l.SnapshotId == id));
+    }
+
+    [Fact]
+    public async Task Create_WithNoLines_Throws()
+    {
+        var (svc, _) = Build();
+        var r = Rent(); r.Lines.Clear();
+        await Assert.ThrowsAsync<InvalidOperationException>(() => svc.CreateAsync(r));
+    }
+
+    [Fact]
+    public async Task GetById_ReturnsLines_TotalsAndCreatorName()
+    {
+        var (svc, db) = Build("creator-1");
+        db.Members.Add(new Member { Id = 5, FirstName_en = "Joy", LastName_en = "Wong" });
+        db.Users.Add(new AppUser { Id = "creator-1", MemberId = 5 });
+        await db.SaveChangesAsync();
+
+        var id = await svc.CreateAsync(Rent());
+        var dto = await svc.GetByIdAsync(id);
+
+        Assert.NotNull(dto);
+        Assert.Equal(1200m, dto!.TotalAmount);
+        Assert.Equal(1, dto.LineCount);
+        Assert.Equal("Rent", dto.Lines.Single().SubCategoryName);
+        Assert.Equal("Joy Wong", dto.CreatedByName);
+    }
+
+    [Fact]
+    public async Task GetAll_ReturnsNewestFirst()
+    {
+        var (svc, _) = Build();
+        var first  = await svc.CreateAsync(Rent());
+        var second = await svc.CreateAsync(Rent());
+
+        var all = await svc.GetAllAsync();
+
+        Assert.Equal(2, all.Count);
+        Assert.Equal(second, all[0].Id);
+        Assert.Equal(first,  all[1].Id);
+    }
+
+    [Fact]
+    public async Task Update_RenamesAndReplacesLines()
+    {
+        var (svc, db) = Build();
+        db.ExpenseCategoryGroups.Add(new ExpenseCategoryGroup { Id = 2, Name_en = "Utilities" });
+        db.ExpenseSubCategories.Add(new ExpenseSubCategory { Id = 2, GroupId = 2, Name_en = "Internet" });
+        await db.SaveChangesAsync();
+
+        var id = await svc.CreateAsync(Rent());
+        await svc.UpdateAsync(id, new UpdateExpenseSnapshotRequest
+        {
+            Name = "Monthly Internet", MinistryId = 1, Description = "ISP",
+            Lines = { new ExpenseLineInput { CategoryGroupId = 2, SubCategoryId = 2, Amount = 80m } },
+        });
+
+        var dto = await svc.GetByIdAsync(id);
+        Assert.Equal("Monthly Internet", dto!.Name);
+        Assert.Equal(80m, dto.TotalAmount);
+        Assert.Equal("Internet", dto.Lines.Single().SubCategoryName);
+        Assert.Equal(1, await db.ExpenseSnapshotLines.CountAsync(l => l.SnapshotId == id));
+    }
+
+    [Fact]
+    public async Task Update_MissingId_Throws()
+    {
+        var (svc, _) = Build();
+        await Assert.ThrowsAsync<KeyNotFoundException>(() => svc.UpdateAsync(999, new UpdateExpenseSnapshotRequest
+        {
+            Name = "x", MinistryId = 1, Description = "x",
+            Lines = { new ExpenseLineInput { CategoryGroupId = 1, SubCategoryId = 1, Amount = 1m } },
+        }));
+    }
+
+    [Fact]
+    public async Task Delete_SoftDeletes_HidesFromQueries()
+    {
+        var (svc, db) = Build();
+        var id = await svc.CreateAsync(Rent());
+
+        await svc.DeleteAsync(id);
+
+        Assert.Empty(await svc.GetAllAsync());
+        Assert.Null(await db.ExpenseSnapshots.FirstOrDefaultAsync(s => s.Id == id));
+    }
+}
diff --git a/API/ROLAC.API/Services/ExpenseSnapshotService.cs b/API/ROLAC.API/Services/ExpenseSnapshotService.cs
new file mode 100644
index 0000000..cd85877
--- /dev/null
+++ b/API/ROLAC.API/Services/ExpenseSnapshotService.cs
@@ -0,0 +1,151 @@
+using Microsoft.EntityFrameworkCore;
+using ROLAC.API.Data;
+using ROLAC.API.DTOs.Expense;
+using ROLAC.API.Entities;
+
+namespace ROLAC.API.Services;
+
+public class ExpenseSnapshotService : IExpenseSnapshotService
+{
+    private readonly AppDbContext _db;
+    public ExpenseSnapshotService(AppDbContext db) => _db = db;
+
+    public async Task<List<ExpenseSnapshotDto>> GetAllAsync()
+    {
+        var snaps = await _db.ExpenseSnapshots.AsNoTracking()
+            .OrderByDescending(s => s.CreatedAt).ThenByDescending(s => s.Id)
+            .ToListAsync();
+        if (snaps.Count == 0) return new();
+
+        var ids = snaps.Select(s => s.Id).ToList();
+        var lines = await _db.ExpenseSnapshotLines.AsNoTracking()
+            .Where(l => ids.Contains(l.SnapshotId)).ToListAsync();
+        var linesBySnapshot = lines.GroupBy(l => l.SnapshotId).ToDictionary(g => g.Key, g => g.ToList());
+
+        var minNames = await _db.Ministries.AsNoTracking().ToDictionaryAsync(m => m.Id, m => $"{m.Name_en} / {m.Name_zh}");
+        var creatorNames = await ResolveUserNamesAsync(snaps.Select(s => s.CreatedBy));
+
+        return snaps.Select(s =>
+        {
+            linesBySnapshot.TryGetValue(s.Id, out var ls);
+            return new ExpenseSnapshotDto
+            {
+                Id = s.Id, Name = s.Name, MinistryId = s.MinistryId,
+                MinistryName = minNames.GetValueOrDefault(s.MinistryId, ""),
+                Description = s.Description, VendorName = s.VendorName,
+                CheckNumber = s.CheckNumber, Notes = s.Notes,
+                TotalAmount = ls?.Sum(l => l.Amount) ?? 0,
+                LineCount = ls?.Count ?? 0,
+                CreatedByName = creatorNames.GetValueOrDefault(s.CreatedBy),
+                CreatedAt = s.CreatedAt,
+            };
+        }).ToList();
+    }
+
+    public async Task<ExpenseSnapshotDto?> GetByIdAsync(int id)
+    {
+        var s = await _db.ExpenseSnapshots.AsNoTracking().FirstOrDefaultAsync(x => x.Id == id);
+        if (s is null) return null;
+
+        var lines = await _db.ExpenseSnapshotLines.AsNoTracking()
+            .Where(l => l.SnapshotId == id).OrderBy(l => l.Id).ToListAsync();
+        var minName = await _db.Ministries.Where(m => m.Id == s.MinistryId).Select(m => m.Name_en).FirstOrDefaultAsync() ?? "";
+        var grpNames = await _db.ExpenseCategoryGroups.AsNoTracking().ToDictionaryAsync(g => g.Id, g => g.Name_en);
+        var subNames = await _db.ExpenseSubCategories.AsNoTracking().ToDictionaryAsync(x => x.Id, x => x.Name_en);
+        var creatorName = (await ResolveUserNamesAsync(new[] { s.CreatedBy })).GetValueOrDefault(s.CreatedBy);
+
+        return new ExpenseSnapshotDto
+        {
+            Id = s.Id, Name = s.Name, MinistryId = s.MinistryId, MinistryName = minName,
+            Description = s.Description, VendorName = s.VendorName, CheckNumber = s.CheckNumber, Notes = s.Notes,
+            TotalAmount = lines.Sum(l => l.Amount), LineCount = lines.Count,
+            CreatedByName = creatorName, CreatedAt = s.CreatedAt,
+            Lines = lines.Select(l => new ExpenseSnapshotLineDto
+            {
+                CategoryGroupId = l.CategoryGroupId, CategoryGroupName = grpNames.GetValueOrDefault(l.CategoryGroupId, ""),
+                SubCategoryId = l.SubCategoryId, SubCategoryName = subNames.GetValueOrDefault(l.SubCategoryId, ""),
+                FunctionalClass = l.FunctionalClass, Amount = l.Amount, Description = l.Description,
+            }).ToList(),
+        };
+    }
+
+    public async Task<int> CreateAsync(CreateExpenseSnapshotRequest r)
+    {
+        ValidateLines(r.Lines);
+        var s = new ExpenseSnapshot
+        {
+            Name = r.Name.Trim(), MinistryId = r.MinistryId, Description = r.Description,
+            VendorName = r.VendorName, CheckNumber = r.CheckNumber, Notes = r.Notes,
+            Lines = BuildLines(r.Lines),
+        };
+        _db.ExpenseSnapshots.Add(s);
+        await _db.SaveChangesAsync();
+        return s.Id;
+    }
+
+    public async Task UpdateAsync(int id, UpdateExpenseSnapshotRequest r)
+    {
+        ValidateLines(r.Lines);
+        var s = await _db.ExpenseSnapshots.Include(x => x.Lines).FirstOrDefaultAsync(x => x.Id == id)
+            ?? throw new KeyNotFoundException($"Snapshot {id} not found.");
+
+        s.Name = r.Name.Trim(); s.MinistryId = r.MinistryId; s.Description = r.Description;
+        s.VendorName = r.VendorName; s.CheckNumber = r.CheckNumber; s.Notes = r.Notes;
+
+        _db.ExpenseSnapshotLines.RemoveRange(s.Lines);
+        s.Lines = BuildLines(r.Lines);
+        await _db.SaveChangesAsync();
+    }
+
+    public async Task DeleteAsync(int id)
+    {
+        var s = await _db.ExpenseSnapshots.FirstOrDefaultAsync(x => x.Id == id)
+            ?? throw new KeyNotFoundException($"Snapshot {id} not found.");
+        s.IsDeleted = true; s.DeletedAt = DateTimeOffset.UtcNow;
+        await _db.SaveChangesAsync();
+    }
+
+    private static void ValidateLines(List<ExpenseLineInput> lines)
+    {
+        if (lines is null || lines.Count == 0)
+            throw new InvalidOperationException("A snapshot must have at least one line.");
+        foreach (var l in lines)
+        {
+            if (l.CategoryGroupId <= 0 || l.SubCategoryId <= 0)
+                throw new InvalidOperationException("Each snapshot line needs a category group and subcategory.");
+            if (l.Amount <= 0)
+                throw new InvalidOperationException("Each snapshot line amount must be greater than zero.");
+        }
+    }
+
+    private static List<ExpenseSnapshotLine> BuildLines(List<ExpenseLineInput> inputs) =>
+        inputs.Select(l => new ExpenseSnapshotLine
+        {
+            CategoryGroupId = l.CategoryGroupId, SubCategoryId = l.SubCategoryId,
+            FunctionalClass = l.FunctionalClass, Amount = l.Amount, Description = l.Description,
+        }).ToList();
+
+    // Resolve actor user ids (AppUser.Id, stored in CreatedBy) to a display name: the linked
+    // Member's full name when present, otherwise the account email. Mirrors ExpenseService.
+    private async Task<Dictionary<string, string>> ResolveUserNamesAsync(IEnumerable<string?> userIds)
+    {
+        var ids = userIds.Where(id => !string.IsNullOrEmpty(id)).Select(id => id!).Distinct().ToList();
+        if (ids.Count == 0) return new();
+
+        var users = await _db.Users.AsNoTracking()
+            .Where(u => ids.Contains(u.Id))
+            .Select(u => new { u.Id, u.Email, u.MemberId })
+            .ToListAsync();
+
+        var memberIds = users.Where(u => u.MemberId != null).Select(u => u.MemberId!.Value).ToHashSet();
+        var memberNames = await _db.Members.AsNoTracking()
+            .Where(m => memberIds.Contains(m.Id))
+            .ToDictionaryAsync(m => m.Id, m => $"{m.FirstName_en} {m.LastName_en}".Trim());
+
+        return users.ToDictionary(
+            u => u.Id,
+            u => u.MemberId != null && memberNames.TryGetValue(u.MemberId.Value, out var name) && name.Length > 0
+                ? name
+                : (u.Email ?? u.Id));
+    }
+}
diff --git a/API/ROLAC.API/Services/IExpenseSnapshotService.cs b/API/ROLAC.API/Services/IExpenseSnapshotService.cs
new file mode 100644
index 0000000..db87623
--- /dev/null
+++ b/API/ROLAC.API/Services/IExpenseSnapshotService.cs
@@ -0,0 +1,11 @@
+using ROLAC.API.DTOs.Expense;
+namespace ROLAC.API.Services;
+
+public interface IExpenseSnapshotService
+{
+    Task<List<ExpenseSnapshotDto>> GetAllAsync();
+    Task<ExpenseSnapshotDto?>      GetByIdAsync(int id);
+    Task<int>                      CreateAsync(CreateExpenseSnapshotRequest r);
+    Task                           UpdateAsync(int id, UpdateExpenseSnapshotRequest r);
+    Task                           DeleteAsync(int id);
+}