Add structured quantities + units to shopping list items

Mirrors the Phase 2 work on RecipeIngredient: ShoppingListItem grows
Quantity (decimal), UnitOfMeasureId / FamilyUnitOfMeasureId, IsApproximate,
and QuantityNote. The recipe-to-list copy now carries structured fields
verbatim instead of folding them into the free-form Name, and the
unit-in-use guard now also blocks deleting a family unit that's referenced
by a shopping list item.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/backend/YesChef.Api.IntegrationTests/Builders/ShoppingListBuilder.cs

@@ -21,9 +21,35 @@ public sealed class ShoppingListBuilder
     public ShoppingListBuilder ForFamily(Family family) { _familyId = family.Id; return this; }
     public ShoppingListBuilder Archived() { _archived = true; return this; }
 
-    public ShoppingListBuilder WithItem(string name, bool isChecked = false, int sortOrder = 0)
+    public ShoppingListBuilder WithItem(
+        string name,
+        bool isChecked = false,
+        int sortOrder = 0,
+        decimal? quantity = null,
+        int? unitOfMeasureId = null,
+        int? familyUnitOfMeasureId = null)
     {
-        _items.Add(new ShoppingListItem { Name = name, IsChecked = isChecked, SortOrder = sortOrder });
+        _items.Add(new ShoppingListItem
+        {
+            Name = name,
+            IsChecked = isChecked,
+            SortOrder = sortOrder,
+            Quantity = quantity,
+            UnitOfMeasureId = unitOfMeasureId,
+            FamilyUnitOfMeasureId = familyUnitOfMeasureId,
+        });
+        return this;
+    }
+
+    public ShoppingListBuilder WithApproximateItem(string name, string quantityNote, int sortOrder = 0)
+    {
+        _items.Add(new ShoppingListItem
+        {
+            Name = name,
+            SortOrder = sortOrder,
+            IsApproximate = true,
+            QuantityNote = quantityNote,
+        });
         return this;
     }
 

src/backend/YesChef.Api.IntegrationTests/Features/ShoppingListEndpointsTests.cs

@@ -441,7 +441,7 @@ public class ShoppingListEndpointsTests : AuthenticatedIntegrationTest
     }
 
     [Test]
-    public async Task Add_recipe_appends_all_ingredients_with_quantity_prefix()
+    public async Task Add_recipe_copies_structured_quantity_to_items()
     {
         var cupId = await UseDbAsync(async db =>
         {
@@ -471,10 +471,134 @@ public class ShoppingListEndpointsTests : AuthenticatedIntegrationTest
         await Assert.That(items.Count).IsEqualTo(4);
         await Assert.That(items.Select(i => i.Name)).IsEquivalentTo(new[]
         {
-            "existing", "2 cup flour", "2 eggs", "salt (to taste)"
+            "existing", "flour", "eggs", "salt"
         });
         await Assert.That(items.Where(i => i.RecipeId == recipe.Id).Count()).IsEqualTo(3);
-        await Assert.That(items[3].SortOrder).IsGreaterThan(5);
+
+        var flour = items.Single(i => i.Name == "flour");
+        await Assert.That(flour.Quantity).IsEqualTo(2m);
+        await Assert.That(flour.UnitOfMeasureId).IsEqualTo(cupId);
+        await Assert.That(flour.IsApproximate).IsFalse();
+
+        var eggs = items.Single(i => i.Name == "eggs");
+        await Assert.That(eggs.Quantity).IsEqualTo(2m);
+        await Assert.That(eggs.UnitOfMeasureId).IsNull();
+
+        var salt = items.Single(i => i.Name == "salt");
+        await Assert.That(salt.IsApproximate).IsTrue();
+        await Assert.That(salt.QuantityNote).IsEqualTo("to taste");
+        await Assert.That(salt.Quantity).IsNull();
+    }
+
+    [Test]
+    public async Task Add_item_persists_structured_quantity()
+    {
+        var cupId = await UseDbAsync(async db =>
+        {
+            var u = new UnitOfMeasure
+            {
+                Code = "cup", SingularName = "cup", PluralName = "cups",
+                Abbreviation = "cup", Category = UnitCategory.Volume,
+            };
+            db.UnitsOfMeasure.Add(u);
+            await db.SaveChangesAsync();
+            return u.Id;
+        });
+        var list = await CreateListAsync();
+
+        var response = await Client.PostAsJsonAsync($"/api/lists/{list.Id}/items",
+            new ShoppingListEndpoints.AddItemRequest("flour", Quantity: 2.5m, UnitOfMeasureId: cupId));
+
+        await Assert.That(response.StatusCode).IsEqualTo(HttpStatusCode.Created);
+        var item = await UseDbAsync(db => db.ShoppingListItems.SingleAsync());
+        await Assert.That(item.Quantity).IsEqualTo(2.5m);
+        await Assert.That(item.UnitOfMeasureId).IsEqualTo(cupId);
+        await Assert.That(item.IsApproximate).IsFalse();
+    }
+
+    [Test]
+    public async Task Add_item_persists_approximate_note_and_clears_structured_fields()
+    {
+        var list = await CreateListAsync();
+
+        var response = await Client.PostAsJsonAsync($"/api/lists/{list.Id}/items",
+            new ShoppingListEndpoints.AddItemRequest("salt", Quantity: 1m, IsApproximate: true, QuantityNote: "to taste"));
+
+        await Assert.That(response.StatusCode).IsEqualTo(HttpStatusCode.Created);
+        var item = await UseDbAsync(db => db.ShoppingListItems.SingleAsync());
+        await Assert.That(item.IsApproximate).IsTrue();
+        await Assert.That(item.QuantityNote).IsEqualTo("to taste");
+        await Assert.That(item.Quantity).IsNull();
+        await Assert.That(item.UnitOfMeasureId).IsNull();
+    }
+
+    [Test]
+    public async Task Add_item_rejects_setting_both_unit_ids()
+    {
+        var list = await CreateListAsync();
+
+        var response = await Client.PostAsJsonAsync($"/api/lists/{list.Id}/items",
+            new ShoppingListEndpoints.AddItemRequest("flour", UnitOfMeasureId: 1, FamilyUnitOfMeasureId: 1));
+
+        await Assert.That(response.StatusCode).IsEqualTo(HttpStatusCode.BadRequest);
+    }
+
+    [Test]
+    public async Task Add_item_rejects_other_familys_family_unit()
+    {
+        var list = await CreateListAsync();
+        var foreignUnitId = await UseDbAsync(async db =>
+        {
+            var otherFamily = new Family { Name = "Other-Unit", InviteCode = "other-unit-code" };
+            db.Families.Add(otherFamily);
+            await db.SaveChangesAsync();
+            var u = new FamilyUnitOfMeasure
+            {
+                FamilyId = otherFamily.Id,
+                SingularName = "scoop", PluralName = "scoops",
+                Abbreviation = "scp", Category = UnitCategory.Count,
+            };
+            db.FamilyUnitsOfMeasure.Add(u);
+            await db.SaveChangesAsync();
+            return u.Id;
+        });
+
+        var response = await Client.PostAsJsonAsync($"/api/lists/{list.Id}/items",
+            new ShoppingListEndpoints.AddItemRequest("flour", FamilyUnitOfMeasureId: foreignUnitId));
+
+        await Assert.That(response.StatusCode).IsEqualTo(HttpStatusCode.BadRequest);
+    }
+
+    [Test]
+    public async Task Get_list_projects_structured_quantity_fields()
+    {
+        var cupId = await UseDbAsync(async db =>
+        {
+            var u = new UnitOfMeasure
+            {
+                Code = "cup-proj", SingularName = "cup", PluralName = "cups",
+                Abbreviation = "cup-proj", Category = UnitCategory.Volume,
+            };
+            db.UnitsOfMeasure.Add(u);
+            await db.SaveChangesAsync();
+            return u.Id;
+        });
+        var list = await CreateListAsync(b => b
+            .WithItem("flour", quantity: 3m, unitOfMeasureId: cupId)
+            .WithApproximateItem("salt", "to taste", sortOrder: 2));
+
+        var body = await Client.GetFromJsonAsync<JsonElement>($"/api/lists/{list.Id}");
+        var items = body.GetProperty("items").EnumerateArray().ToArray();
+
+        var flour = items.Single(i => i.GetProperty("name").GetString() == "flour");
+        await Assert.That(flour.GetProperty("quantity").GetDecimal()).IsEqualTo(3m);
+        await Assert.That(flour.GetProperty("unitOfMeasureId").GetInt32()).IsEqualTo(cupId);
+        await Assert.That(flour.GetProperty("isApproximate").GetBoolean()).IsFalse();
+
+        var salt = items.Single(i => i.GetProperty("name").GetString() == "salt");
+        await Assert.That(salt.GetProperty("isApproximate").GetBoolean()).IsTrue();
+        await Assert.That(salt.GetProperty("quantityNote").GetString()).IsEqualTo("to taste");
+        await Assert.That(salt.GetProperty("quantity").ValueKind).IsEqualTo(JsonValueKind.Null);
     }
 
     [Test]

src/backend/YesChef.Api.IntegrationTests/Features/UnitEndpointsTests.cs

@@ -234,6 +234,43 @@ public class UnitEndpointsTests : AuthenticatedIntegrationTest
         await Assert.That(remaining).IsEqualTo(1);
     }
 
+    [Test]
+    public async Task Delete_family_unit_returns_409_when_referenced_by_shopping_list_item()
+    {
+        var familyId = await GetFamilyIdAsync();
+        var store = await Data.CreateStoreAsync();
+        var unit = await UseDbAsync(async db =>
+        {
+            var u = new FamilyUnitOfMeasure
+            {
+                FamilyId = familyId,
+                SingularName = "scoop", PluralName = "scoops",
+                Abbreviation = "scp", Category = UnitCategory.Count,
+            };
+            db.FamilyUnitsOfMeasure.Add(u);
+            await db.SaveChangesAsync();
+
+            var list = new ShoppingList
+            {
+                FamilyId = familyId,
+                Name = "List with unit",
+                StoreId = store.Id,
+                CreatedByUserId = User.Id,
+                Items = new List<ShoppingListItem>
+                {
+                    new() { FamilyId = familyId, Name = "ice cream", Quantity = 2m, FamilyUnitOfMeasureId = u.Id },
+                },
+            };
+            db.ShoppingLists.Add(list);
+            await db.SaveChangesAsync();
+            return u;
+        });
+
+        var response = await Client.DeleteAsync($"/api/units/family/{unit.Id}");
+
+        await Assert.That(response.StatusCode).IsEqualTo(HttpStatusCode.Conflict);
+    }
+
     [Test]
     public async Task Endpoints_require_authentication()
     {

src/backend/YesChef.Api/Data/YesChefDb.cs

@@ -95,6 +95,8 @@ public class YesChefDb(DbContextOptions<YesChefDb> options) : DbContext(options)
         modelBuilder.Entity<ShoppingListItem>(e =>
         {
             e.Property(i => i.Name).HasMaxLength(300);
+            e.Property(i => i.Quantity).HasPrecision(12, 4);
+            e.Property(i => i.QuantityNote).HasMaxLength(200);
             e.HasOne(i => i.Family).WithMany().HasForeignKey(i => i.FamilyId).OnDelete(DeleteBehavior.Cascade);
             e.HasOne(i => i.CheckedByUser).WithMany().HasForeignKey(i => i.CheckedByUserId).OnDelete(DeleteBehavior.SetNull);
             e.HasOne(i => i.RemovedByUser).WithMany().HasForeignKey(i => i.RemovedByUserId).OnDelete(DeleteBehavior.SetNull);
@@ -102,6 +104,10 @@ public class YesChefDb(DbContextOptions<YesChefDb> options) : DbContext(options)
             e.HasOne(i => i.Section).WithMany().HasForeignKey(i => i.SectionId).OnDelete(DeleteBehavior.SetNull);
             e.HasOne(i => i.Product).WithMany().HasForeignKey(i => i.ProductId).OnDelete(DeleteBehavior.SetNull);
             e.HasOne(i => i.FamilyProduct).WithMany().HasForeignKey(i => i.FamilyProductId).OnDelete(DeleteBehavior.SetNull);
+            // Restrict on delete: the unit-delete endpoint already blocks
+            // deletion when an item references the unit; this is defense in depth.
+            e.HasOne(i => i.UnitOfMeasure).WithMany().HasForeignKey(i => i.UnitOfMeasureId).OnDelete(DeleteBehavior.Restrict);
+            e.HasOne(i => i.FamilyUnitOfMeasure).WithMany().HasForeignKey(i => i.FamilyUnitOfMeasureId).OnDelete(DeleteBehavior.Restrict);
             e.HasIndex(i => i.FamilyId);
         });
 

src/backend/YesChef.Api/Entities/ShoppingListItem.cs

@@ -22,6 +22,17 @@ public class ShoppingListItem
     public Product? Product { get; set; }
     public int? FamilyProductId { get; set; }
     public FamilyProduct? FamilyProduct { get; set; }
+    // Structured quantity. Null = unspecified (free-form Name carries the meaning).
+    public decimal? Quantity { get; set; }
+    // At most one of UnitOfMeasureId / FamilyUnitOfMeasureId is set on a row.
+    public int? UnitOfMeasureId { get; set; }
+    public UnitOfMeasure? UnitOfMeasure { get; set; }
+    public int? FamilyUnitOfMeasureId { get; set; }
+    public FamilyUnitOfMeasure? FamilyUnitOfMeasure { get; set; }
+    // Approximations like "to taste" / "a pinch" — render QuantityNote instead
+    // of the structured Quantity/Unit pair when this flag is set.
+    public bool IsApproximate { get; set; }
+    public string? QuantityNote { get; set; }
     public DateTime CreatedAt { get; set; } = DateTime.UtcNow;
     public DateTime? RemovedAt { get; set; }
     public int? RemovedByUserId { get; set; }

src/backend/YesChef.Api/Features/ShoppingLists/ShoppingListEndpoints.cs

@@ -10,7 +10,17 @@ public static class ShoppingListEndpoints
 {
     public record CreateListRequest(string Name, int StoreId);
     public record UpdateListRequest(string Name, int StoreId);
-    public record AddItemRequest(string Name, int SortOrder = 0, int? SectionId = null, int? ProductId = null, int? FamilyProductId = null);
+    public record AddItemRequest(
+        string Name,
+        int SortOrder = 0,
+        int? SectionId = null,
+        int? ProductId = null,
+        int? FamilyProductId = null,
+        decimal? Quantity = null,
+        int? UnitOfMeasureId = null,
+        int? FamilyUnitOfMeasureId = null,
+        bool IsApproximate = false,
+        string? QuantityNote = null);
     public record SetItemSectionRequest(int? SectionId);
 
     private static string OverviewGroup(int familyId) => $"lists-overview-{familyId}";
@@ -129,7 +139,12 @@ public static class ShoppingListEndpoints
                     i.SectionId,
                     RecipeTitle = i.Recipe?.Title,
                     i.ProductId,
-                    i.FamilyProductId
+                    i.FamilyProductId,
+                    i.Quantity,
+                    i.UnitOfMeasureId,
+                    i.FamilyUnitOfMeasureId,
+                    i.IsApproximate,
+                    i.QuantityNote
                 })
             });
         });
@@ -183,6 +198,9 @@ public static class ShoppingListEndpoints
             if (await ValidateProductLink(db, familyId, request.ProductId, request.FamilyProductId) is { } productError)
                 return productError;
 
+            if (await ValidateUnitLink(db, familyId, request.UnitOfMeasureId, request.FamilyUnitOfMeasureId) is { } unitError)
+                return unitError;
+
             // Auto-assign a section from memory when caller didn't pick one
             // but supplied a product link — "we put bananas in Produce last
             // time we shopped here, do it again."
@@ -198,6 +216,11 @@ public static class ShoppingListEndpoints
                 SectionId = resolvedSectionId,
                 ProductId = request.ProductId,
                 FamilyProductId = request.FamilyProductId,
+                Quantity = request.IsApproximate ? null : request.Quantity,
+                UnitOfMeasureId = request.IsApproximate ? null : request.UnitOfMeasureId,
+                FamilyUnitOfMeasureId = request.IsApproximate ? null : request.FamilyUnitOfMeasureId,
+                IsApproximate = request.IsApproximate,
+                QuantityNote = request.IsApproximate ? request.QuantityNote : null,
             };
             db.ShoppingListItems.Add(item);
             list.UpdatedAt = DateTime.UtcNow;
@@ -210,9 +233,9 @@ public static class ShoppingListEndpoints
 
             await db.SaveChangesAsync();
 
-            await hub.Clients.Group($"list-{listId}").SendAsync("ItemAdded", new { item.Id, item.Name, item.SortOrder, item.SectionId, item.ProductId, item.FamilyProductId });
+            await hub.Clients.Group($"list-{listId}").SendAsync("ItemAdded", ItemAddedPayload(item, recipeTitle: null));
             await BroadcastListSummary(hub, db, listId, familyId);
-            return Results.Created($"/api/lists/{listId}/items/{item.Id}", new { item.Id, item.Name, item.SortOrder, item.SectionId, item.ProductId, item.FamilyProductId });
+            return Results.Created($"/api/lists/{listId}/items/{item.Id}", ItemAddedPayload(item, recipeTitle: null));
         });
 
         group.MapPatch("/{listId:int}/items/{itemId:int}/section", async (int listId, int itemId, SetItemSectionRequest request, YesChefDb db, HttpContext http, IHubContext<ShoppingListHub> hub) =>
@@ -297,7 +320,12 @@ public static class ShoppingListEndpoints
                 item.SectionId,
                 RecipeTitle = item.Recipe?.Title,
                 item.ProductId,
-                item.FamilyProductId
+                item.FamilyProductId,
+                item.Quantity,
+                item.UnitOfMeasureId,
+                item.FamilyUnitOfMeasureId,
+                item.IsApproximate,
+                item.QuantityNote
             });
             await BroadcastListSummary(hub, db, listId, familyId);
             return Results.NoContent();
@@ -330,16 +358,17 @@ public static class ShoppingListEndpoints
                 {
                     FamilyId = familyId,
                     ShoppingListId = listId,
-                    // Phase 3 will give ShoppingListItem its own structured
+                    Name = ing.Name,
-                    // quantity/unit fields. Until then, fold the recipe's
-                    // structured quantity into the free-form Name so the
-                    // list still reads "2 cup flour" / "salt to taste".
-                    Name = FormatIngredientForList(ing),
                     SortOrder = maxSort + idx + 1,
                     RecipeId = recipeId,
                     ProductId = ing.ProductId,
                     FamilyProductId = ing.FamilyProductId,
                     SectionId = rememberedSectionId,
+                    Quantity = ing.Quantity,
+                    UnitOfMeasureId = ing.UnitOfMeasureId,
+                    FamilyUnitOfMeasureId = ing.FamilyUnitOfMeasureId,
+                    IsApproximate = ing.IsApproximate,
+                    QuantityNote = ing.QuantityNote,
                 });
                 idx++;
             }
@@ -350,7 +379,7 @@ public static class ShoppingListEndpoints
 
             foreach (var item in newItems)
             {
-                await hub.Clients.Group($"list-{listId}").SendAsync("ItemAdded", new { item.Id, item.Name, item.SortOrder, item.SectionId, item.ProductId, item.FamilyProductId, RecipeTitle = recipe.Title });
+                await hub.Clients.Group($"list-{listId}").SendAsync("ItemAdded", ItemAddedPayload(item, recipe.Title));
             }
 
             await BroadcastListSummary(hub, db, listId, familyId);
@@ -380,24 +409,25 @@ public static class ShoppingListEndpoints
     }
 
     /// <summary>
-    /// Render an ingredient's structured quantity into a free-form display
+    /// Shape the wire payload for ItemAdded / Created responses so clients
-    /// string for use as a shopping list item Name in Phase 2. Phase 3 will
+    /// can render the structured quantity. Single source of truth so the
-    /// remove this once ShoppingListItem grows its own structured fields.
+    /// list endpoint and recipe-add fan-out stay aligned.
     /// </summary>
-    private static string FormatIngredientForList(RecipeIngredient ing)
+    private static object ItemAddedPayload(ShoppingListItem item, string? recipeTitle) => new
     {
-        if (ing.IsApproximate && !string.IsNullOrWhiteSpace(ing.QuantityNote))
+        item.Id,
-            return $"{ing.Name} ({ing.QuantityNote})";
+        item.Name,
-
+        item.SortOrder,
-        var abbrev = ing.UnitOfMeasure?.Abbreviation ?? ing.FamilyUnitOfMeasure?.Abbreviation;
+        item.SectionId,
-        if (ing.Quantity is { } q)
+        item.ProductId,
-        {
+        item.FamilyProductId,
-            // Trim trailing zeros so "2.0000" renders as "2".
+        item.Quantity,
-            var qty = q.ToString("0.####", System.Globalization.CultureInfo.InvariantCulture);
+        item.UnitOfMeasureId,
-            return string.IsNullOrEmpty(abbrev) ? $"{qty} {ing.Name}" : $"{qty} {abbrev} {ing.Name}";
+        item.FamilyUnitOfMeasureId,
-        }
+        item.IsApproximate,
-        return ing.Name;
+        item.QuantityNote,
-    }
+        RecipeTitle = recipeTitle,
+    };
 
     /// <summary>
     /// Validates the unit-of-measure FK pair on an ingredient/item payload.

src/backend/YesChef.Api/Features/Units/UnitEndpoints.cs

@@ -119,10 +119,12 @@ public static class UnitEndpoints
             var unit = await db.FamilyUnitsOfMeasure.FirstOrDefaultAsync(u => u.Id == id && u.FamilyId == familyId);
             if (unit is null) return Results.NotFound();
 
-            // Block deletion when any recipe ingredient still references the
+            // Block deletion when any recipe ingredient or shopping list item
-            // unit. (ShoppingListItem will gain the same check in Phase 3.)
+            // still references the unit.
-            var inUse = await db.RecipeIngredients.AnyAsync(i => i.FamilyUnitOfMeasureId == id);
+            var inUseByRecipe = await db.RecipeIngredients.AnyAsync(i => i.FamilyUnitOfMeasureId == id);
-            if (inUse) return Results.Conflict(new { error = "Unit is in use by one or more recipes." });
+            if (inUseByRecipe) return Results.Conflict(new { error = "Unit is in use by one or more recipes." });
+            var inUseByList = await db.ShoppingListItems.AnyAsync(i => i.FamilyUnitOfMeasureId == id);
+            if (inUseByList) return Results.Conflict(new { error = "Unit is in use by one or more shopping lists." });
 
             db.FamilyUnitsOfMeasure.Remove(unit);
             await db.SaveChangesAsync();

src/backend/YesChef.Api/Migrations/20260513233141_AddStructuredShoppingListItemQuantities.cs

@@ -0,0 +1,114 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace YesChef.Api.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddStructuredShoppingListItemQuantities : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<int>(
+                name: "FamilyUnitOfMeasureId",
+                table: "ShoppingListItems",
+                type: "integer",
+                nullable: true);
+
+            migrationBuilder.AddColumn<bool>(
+                name: "IsApproximate",
+                table: "ShoppingListItems",
+                type: "boolean",
+                nullable: false,
+                defaultValue: false);
+
+            migrationBuilder.AddColumn<decimal>(
+                name: "Quantity",
+                table: "ShoppingListItems",
+                type: "numeric(12,4)",
+                precision: 12,
+                scale: 4,
+                nullable: true);
+
+            migrationBuilder.AddColumn<string>(
+                name: "QuantityNote",
+                table: "ShoppingListItems",
+                type: "character varying(200)",
+                maxLength: 200,
+                nullable: true);
+
+            migrationBuilder.AddColumn<int>(
+                name: "UnitOfMeasureId",
+                table: "ShoppingListItems",
+                type: "integer",
+                nullable: true);
+
+            migrationBuilder.CreateIndex(
+                name: "IX_ShoppingListItems_FamilyUnitOfMeasureId",
+                table: "ShoppingListItems",
+                column: "FamilyUnitOfMeasureId");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_ShoppingListItems_UnitOfMeasureId",
+                table: "ShoppingListItems",
+                column: "UnitOfMeasureId");
+
+            migrationBuilder.AddForeignKey(
+                name: "FK_ShoppingListItems_FamilyUnitsOfMeasure_FamilyUnitOfMeasureId",
+                table: "ShoppingListItems",
+                column: "FamilyUnitOfMeasureId",
+                principalTable: "FamilyUnitsOfMeasure",
+                principalColumn: "Id",
+                onDelete: ReferentialAction.Restrict);
+
+            migrationBuilder.AddForeignKey(
+                name: "FK_ShoppingListItems_UnitsOfMeasure_UnitOfMeasureId",
+                table: "ShoppingListItems",
+                column: "UnitOfMeasureId",
+                principalTable: "UnitsOfMeasure",
+                principalColumn: "Id",
+                onDelete: ReferentialAction.Restrict);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropForeignKey(
+                name: "FK_ShoppingListItems_FamilyUnitsOfMeasure_FamilyUnitOfMeasureId",
+                table: "ShoppingListItems");
+
+            migrationBuilder.DropForeignKey(
+                name: "FK_ShoppingListItems_UnitsOfMeasure_UnitOfMeasureId",
+                table: "ShoppingListItems");
+
+            migrationBuilder.DropIndex(
+                name: "IX_ShoppingListItems_FamilyUnitOfMeasureId",
+                table: "ShoppingListItems");
+
+            migrationBuilder.DropIndex(
+                name: "IX_ShoppingListItems_UnitOfMeasureId",
+                table: "ShoppingListItems");
+
+            migrationBuilder.DropColumn(
+                name: "FamilyUnitOfMeasureId",
+                table: "ShoppingListItems");
+
+            migrationBuilder.DropColumn(
+                name: "IsApproximate",
+                table: "ShoppingListItems");
+
+            migrationBuilder.DropColumn(
+                name: "Quantity",
+                table: "ShoppingListItems");
+
+            migrationBuilder.DropColumn(
+                name: "QuantityNote",
+                table: "ShoppingListItems");
+
+            migrationBuilder.DropColumn(
+                name: "UnitOfMeasureId",
+                table: "ShoppingListItems");
+        }
+    }
+}

src/backend/YesChef.Api/Migrations/YesChefDbModelSnapshot.cs

@@ -514,6 +514,12 @@ namespace YesChef.Api.Migrations
                     b.Property<int?>("FamilyProductId")
                         .HasColumnType("integer");
 
+                    b.Property<int?>("FamilyUnitOfMeasureId")
+                        .HasColumnType("integer");
+
+                    b.Property<bool>("IsApproximate")
+                        .HasColumnType("boolean");
+
                     b.Property<bool>("IsChecked")
                         .HasColumnType("boolean");
 
@@ -525,6 +531,14 @@ namespace YesChef.Api.Migrations
                     b.Property<int?>("ProductId")
                         .HasColumnType("integer");
 
+                    b.Property<decimal?>("Quantity")
+                        .HasPrecision(12, 4)
+                        .HasColumnType("numeric(12,4)");
+
+                    b.Property<string>("QuantityNote")
+                        .HasMaxLength(200)
+                        .HasColumnType("character varying(200)");
+
                     b.Property<int?>("RecipeId")
                         .HasColumnType("integer");
 
@@ -543,6 +557,9 @@ namespace YesChef.Api.Migrations
                     b.Property<int>("SortOrder")
                         .HasColumnType("integer");
 
+                    b.Property<int?>("UnitOfMeasureId")
+                        .HasColumnType("integer");
+
                     b.HasKey("Id");
 
                     b.HasIndex("CheckedByUserId");
@@ -551,6 +568,8 @@ namespace YesChef.Api.Migrations
 
                     b.HasIndex("FamilyProductId");
 
+                    b.HasIndex("FamilyUnitOfMeasureId");
+
                     b.HasIndex("ProductId");
 
                     b.HasIndex("RecipeId");
@@ -561,6 +580,8 @@ namespace YesChef.Api.Migrations
 
                     b.HasIndex("ShoppingListId");
 
+                    b.HasIndex("UnitOfMeasureId");
+
                     b.ToTable("ShoppingListItems");
                 });
 
@@ -965,6 +986,11 @@ namespace YesChef.Api.Migrations
                         .HasForeignKey("FamilyProductId")
                         .OnDelete(DeleteBehavior.SetNull);
 
+                    b.HasOne("YesChef.Api.Entities.FamilyUnitOfMeasure", "FamilyUnitOfMeasure")
+                        .WithMany()
+                        .HasForeignKey("FamilyUnitOfMeasureId")
+                        .OnDelete(DeleteBehavior.Restrict);
+
                     b.HasOne("YesChef.Api.Entities.Product", "Product")
                         .WithMany()
                         .HasForeignKey("ProductId")
@@ -991,12 +1017,19 @@ namespace YesChef.Api.Migrations
                         .OnDelete(DeleteBehavior.Cascade)
                         .IsRequired();
 
+                    b.HasOne("YesChef.Api.Entities.UnitOfMeasure", "UnitOfMeasure")
+                        .WithMany()
+                        .HasForeignKey("UnitOfMeasureId")
+                        .OnDelete(DeleteBehavior.Restrict);
+
                     b.Navigation("CheckedByUser");
 
                     b.Navigation("Family");
 
                     b.Navigation("FamilyProduct");
 
+                    b.Navigation("FamilyUnitOfMeasure");
+
                     b.Navigation("Product");
 
                     b.Navigation("Recipe");
@@ -1006,6 +1039,8 @@ namespace YesChef.Api.Migrations
                     b.Navigation("Section");
 
                     b.Navigation("ShoppingList");
+
+                    b.Navigation("UnitOfMeasure");
                 });
 
             modelBuilder.Entity("YesChef.Api.Entities.Store", b =>

src/frontend/src/routes/lists/[id]/+page.svelte

@@ -6,6 +6,9 @@
 	import { startConnection, stopConnection } from '$lib/signalr';
 	import { toast } from '$lib/toast.svelte';
 	import ProductTypeahead, { type ProductSuggestion } from '$lib/ProductTypeahead.svelte';
+	import QuantityInput, { type QuantityValue } from '$lib/QuantityInput.svelte';
+	import { units } from '$lib/units.svelte';
+	import { formatQuantity } from '$lib/formatQuantity';
 	import type { HubConnection } from '@microsoft/signalr';
 
 	interface ListItem {
@@ -16,6 +19,11 @@
 		sortOrder: number;
 		sectionId: number | null;
 		recipeTitle: string | null;
+		quantity: number | null;
+		unitOfMeasureId: number | null;
+		familyUnitOfMeasureId: number | null;
+		isApproximate: boolean;
+		quantityNote: string | null;
 	}
 
 	interface Section {
@@ -42,6 +50,9 @@
 	let newItemSectionId = $state<number | null>(null);
 	let newItemProductId = $state<number | null>(null);
 	let newItemFamilyProductId = $state<number | null>(null);
+	let newItemQuantity = $state<QuantityValue>({ quantity: null, unitOfMeasureId: null, familyUnitOfMeasureId: null });
+	let newItemIsApproximate = $state(false);
+	let newItemQuantityNote = $state('');
 	let loading = $state(true);
 	let connection: HubConnection | null = null;
 
@@ -83,12 +94,18 @@
 		list = data;
 		items = data.items;
 		sections = data.sections;
+		// Touch the unit catalog so abbreviations are available for display.
+		void units.all;
 		loading = false;
 
 		connection = await startConnection();
 		await connection.invoke('JoinList', listId);
 
-		connection.on('ItemAdded', (data: { id: number; name: string; sortOrder: number; sectionId: number | null; recipeTitle?: string }) => {
+		connection.on('ItemAdded', (data: {
+			id: number; name: string; sortOrder: number; sectionId: number | null; recipeTitle?: string;
+			quantity: number | null; unitOfMeasureId: number | null; familyUnitOfMeasureId: number | null;
+			isApproximate: boolean; quantityNote: string | null;
+		}) => {
 			if (!items.find((i) => i.id === data.id)) {
 				items = [
 					...items,
@@ -99,7 +116,12 @@
 						checkedByUserName: null,
 						sortOrder: data.sortOrder,
 						sectionId: data.sectionId ?? null,
-						recipeTitle: data.recipeTitle ?? null
+						recipeTitle: data.recipeTitle ?? null,
+						quantity: data.quantity,
+						unitOfMeasureId: data.unitOfMeasureId,
+						familyUnitOfMeasureId: data.familyUnitOfMeasureId,
+						isApproximate: data.isApproximate,
+						quantityNote: data.quantityNote
 					}
 				];
 			}
@@ -154,12 +176,29 @@
 				sortOrder: maxSort + 1,
 				sectionId: newItemSectionId,
 				productId: newItemProductId,
-				familyProductId: newItemFamilyProductId
+				familyProductId: newItemFamilyProductId,
+				quantity: newItemIsApproximate ? null : newItemQuantity.quantity,
+				unitOfMeasureId: newItemIsApproximate ? null : newItemQuantity.unitOfMeasureId,
+				familyUnitOfMeasureId: newItemIsApproximate ? null : newItemQuantity.familyUnitOfMeasureId,
+				isApproximate: newItemIsApproximate,
+				quantityNote: newItemIsApproximate ? (newItemQuantityNote || null) : null
 			})
 		});
 		newItemName = '';
 		newItemProductId = null;
 		newItemFamilyProductId = null;
+		newItemQuantity = { quantity: null, unitOfMeasureId: null, familyUnitOfMeasureId: null };
+		newItemIsApproximate = false;
+		newItemQuantityNote = '';
+	}
+
+	function toggleApproximateNewItem() {
+		newItemIsApproximate = !newItemIsApproximate;
+		if (newItemIsApproximate) {
+			newItemQuantity = { quantity: null, unitOfMeasureId: null, familyUnitOfMeasureId: null };
+		} else {
+			newItemQuantityNote = '';
+		}
 	}
 
 	function onItemProductChange(product: ProductSuggestion | null) {
@@ -229,7 +268,18 @@
 			</button>
 		</div>
 
-		<form onsubmit={e => { e.preventDefault(); addItem(); }} class="mb-4 flex flex-wrap gap-2">
+		<form onsubmit={e => { e.preventDefault(); addItem(); }} class="mb-4 space-y-1">
+			<div class="flex flex-wrap gap-2">
+				{#if newItemIsApproximate}
+					<input
+						type="text"
+						bind:value={newItemQuantityNote}
+						placeholder="e.g. to taste"
+						class="w-36 rounded-lg border border-gray-300 px-2 py-2.5 text-sm focus:border-primary focus:outline-none"
+					/>
+				{:else}
+					<QuantityInput bind:value={newItemQuantity} />
+				{/if}
 				<div class="min-w-0 flex-1">
 					<ProductTypeahead
 						bind:value={newItemName}
@@ -258,6 +308,14 @@
 				>
 					Add
 				</button>
+			</div>
+			<button
+				type="button"
+				onclick={toggleApproximateNewItem}
+				class="text-xs text-gray-500 hover:text-primary"
+			>
+				{newItemIsApproximate ? '↩ use measured amount' : '~ approximate (e.g. to taste)'}
+			</button>
 		</form>
 
 		{#if uncheckedGroups.length > 0}
@@ -269,6 +327,7 @@
 						</h3>
 						<ul class="space-y-1">
 							{#each group.items as item (item.id)}
+								{@const qty = formatQuantity(item, units.all)}
 								<li class="flex items-center gap-3 rounded-lg bg-white px-3 py-3 shadow-sm">
 									<button
 										onclick={() => toggleItem(item.id)}
@@ -276,6 +335,9 @@
 										aria-label="Check {item.name}"
 									></button>
 									<div class="min-w-0 flex-1">
+										{#if qty}
+											<span class="text-base font-medium text-primary">{qty}</span>
+										{/if}
 										<span class="text-base">{item.name}</span>
 										{#if item.recipeTitle}
 											<span class="ml-1 text-xs text-gray-400">from {item.recipeTitle}</span>
@@ -324,6 +386,7 @@
 							</h4>
 							<ul class="space-y-1">
 								{#each group.items as item (item.id)}
+									{@const qty = formatQuantity(item, units.all)}
 									<li class="flex items-center gap-3 rounded-lg bg-white/60 px-3 py-3 shadow-sm">
 										<button
 											onclick={() => toggleItem(item.id)}
@@ -333,6 +396,9 @@
 											✓
 										</button>
 										<div class="min-w-0 flex-1">
+											{#if qty}
+												<span class="text-base text-gray-400 line-through">{qty}</span>
+											{/if}
 											<span class="text-base text-gray-400 line-through">{item.name}</span>
 											{#if item.checkedByUserName}
 												<span class="ml-1 text-xs text-gray-300">{item.checkedByUserName}</span>