diff --git a/src/food-market.api/Controllers/Pos/PosController.cs b/src/food-market.api/Controllers/Pos/PosController.cs
index 83504b7..fb87d00 100644
--- a/src/food-market.api/Controllers/Pos/PosController.cs
+++ b/src/food-market.api/Controllers/Pos/PosController.cs
@@ -64,6 +64,40 @@ public ActionResult<PosVersionDto> Version([FromServices] IConfiguration cfg)
             Mandatory = bool.TryParse(cfg["Pos:Mandatory"], out var m) && m,
         });
 
+    /// <summary>Чек-основание для возврата: поиск проведённого (не-возвратного)
+    /// чека по номеру/QR + позиции с количеством, доступным к возврату
+    /// (продано − уже возвращено). Для экрана возврата на кассе.</summary>
+    [HttpGet("sales/by-number/{number}")]
+    public async Task<ActionResult<PosReturnLookupDto>> SaleByNumber(string number, CancellationToken ct)
+    {
+        var n = (number ?? "").Trim();
+        if (n.Length == 0) return NotFound();
+        var sale = await _db.RetailSales.AsNoTracking()
+            .Where(s => s.Number == n && !s.IsReturn && s.Status == RetailSaleStatus.Posted)
+            .Select(s => new { s.Id, s.Number, s.Date, s.Payment })
+            .FirstOrDefaultAsync(ct);
+        if (sale is null)
+            return NotFound(new { error = "Чек не найден или не проведён.", field = "number" });
+
+        var lines = await (from l in _db.RetailSaleLines.AsNoTracking()
+                           join p in _db.Products.AsNoTracking() on l.ProductId equals p.Id
+                           join u in _db.UnitsOfMeasure.AsNoTracking() on p.UnitOfMeasureId equals u.Id
+                           where l.RetailSaleId == sale.Id
+                           orderby l.SortOrder
+                           select new PosReturnLineDto
+                           {
+                               ProductId = l.ProductId, Name = p.Name, UnitCode = u.Code,
+                               UnitPrice = l.UnitPrice, SoldQty = l.Quantity,
+                               ReturnedQty = l.QtyReturned, ReturnableQty = l.Quantity - l.QtyReturned,
+                           }).ToListAsync(ct);
+
+        return Ok(new PosReturnLookupDto
+        {
+            SaleId = sale.Id, Number = sale.Number, Date = sale.Date,
+            Payment = (int)sale.Payment, Lines = lines,
+        });
+    }
+
     [HttpGet("sync")]
     public async Task<ActionResult<PosSyncResponse>> Sync(
         [FromQuery] DateTime? since,
@@ -312,6 +346,25 @@ public ActionResult<PosVersionDto> Version([FromServices] IConfiguration cfg)
                         $"Недостаточный остаток для товара {x.ProductId}.", "productId");
             }
         }
+        else if (src.ReferenceSaleId is Guid refIdCheck)
+        {
+            // Возврат по чеку: нельзя вернуть больше, чем продано минус уже
+            // возвращено (QtyReturned на исходных строках). Защита от over-return.
+            var refLines = await _db.RetailSaleLines.AsNoTracking()
+                .Where(l => l.RetailSaleId == refIdCheck).ToListAsync(ct);
+            if (refLines.Count == 0)
+                throw new PosSaleRejectedException("Исходный чек не найден.", "referenceSaleId");
+            var remainingByProduct = refLines.GroupBy(l => l.ProductId)
+                .ToDictionary(g => g.Key, g => g.Sum(x => x.Quantity) - g.Sum(x => x.QtyReturned));
+            foreach (var g in src.Lines.GroupBy(l => l.ProductId))
+            {
+                if (!remainingByProduct.TryGetValue(g.Key, out var remaining))
+                    throw new PosSaleRejectedException($"Товар {g.Key} не из исходного чека.", "productId");
+                if (g.Sum(x => x.Quantity) > remaining)
+                    throw new PosSaleRejectedException(
+                        $"Нельзя вернуть больше, чем доступно (к возврату {remaining}).", "quantity");
+            }
+        }
 
         // Привязка к смене: если указана — проверяем, что она открыта и наша.
         if (src.CashShiftId is Guid shiftId)
@@ -394,6 +447,24 @@ public ActionResult<PosVersionDto> Version([FromServices] IConfiguration cfg)
                 UnitCost: l.UnitPrice,
                 OccurredAt: src.OccurredAt), ct);
         }
+        // Возврат по чеку: инкрементим QtyReturned на исходных строках (защита
+        // от повторного возврата той же позиции). Насыщаем по строкам продукта.
+        if (src.IsReturn && src.ReferenceSaleId is Guid refIdInc)
+        {
+            var refLines = await _db.RetailSaleLines
+                .Where(l => l.RetailSaleId == refIdInc).ToListAsync(ct);
+            var takenByProduct = src.Lines.GroupBy(x => x.ProductId)
+                .ToDictionary(g => g.Key, g => g.Sum(x => x.Quantity));
+            foreach (var rl in refLines.OrderBy(l => l.SortOrder))
+            {
+                if (!takenByProduct.TryGetValue(rl.ProductId, out var taken) || taken <= 0) continue;
+                var take = Math.Min(taken, rl.Quantity - rl.QtyReturned);
+                if (take <= 0) continue;
+                rl.QtyReturned += take;
+                takenByProduct[rl.ProductId] = taken - take;
+            }
+        }
+
         sale.Status = RetailSaleStatus.Posted;
         sale.PostedAt = DateTime.UtcNow;
         try
diff --git a/src/food-market.pos.core/Sync/IServerApi.cs b/src/food-market.pos.core/Sync/IServerApi.cs
index 339ca5b..4a0aed1 100644
--- a/src/food-market.pos.core/Sync/IServerApi.cs
+++ b/src/food-market.pos.core/Sync/IServerApi.cs
@@ -18,6 +18,9 @@ public interface IServerApi
     [Get("/api/pos/v1/version")]
     Task<PosVersionDto> VersionAsync(CancellationToken ct = default);
 
+    [Get("/api/pos/v1/sales/by-number/{number}")]
+    Task<PosReturnLookupDto> ReturnLookupAsync(string number, CancellationToken ct = default);
+
     [Get("/api/me")]
     Task<MeDto> MeAsync(CancellationToken ct = default);
 
diff --git a/src/food-market.pos/Services/CheckoutService.cs b/src/food-market.pos/Services/CheckoutService.cs
index 764dc4d..dcb7fb2 100644
--- a/src/food-market.pos/Services/CheckoutService.cs
+++ b/src/food-market.pos/Services/CheckoutService.cs
@@ -56,6 +56,70 @@ public sealed record CommitResult(Guid ClientSaleId, bool PushedNow, int Pending
         return new CommitResult(sale.ClientSaleId, pushedNow, _svc.Store.PendingCount(), printed, printErr);
     }
 
+    /// <summary>Оформить возврат по чеку: собрать return-чек из выбранных позиций
+    /// (IsReturn + ReferenceSaleId), записать в очередь, напечатать, попытаться
+    /// выгрузить. Деньги — к выдаче (refundCash/refundCard как в исходном чеке).</summary>
+    public async Task<CommitResult> CommitReturnAsync(
+        IReadOnlyList<PosSaleLineDto> lines, Guid referenceSaleId,
+        decimal refundCash, decimal refundCard,
+        IReadOnlyList<(string Name, string Unit)> display, CancellationToken ct = default)
+    {
+        if (lines.Count == 0) throw new InvalidOperationException("Не выбрано ни одной позиции для возврата.");
+        var method = (refundCard > 0m && refundCash > 0m) ? PosPaymentMethod.Mixed
+                   : refundCard > 0m ? PosPaymentMethod.Card : PosPaymentMethod.Cash;
+        var sale = new PosSaleDto
+        {
+            ClientSaleId = Guid.NewGuid(), OccurredAt = DateTime.UtcNow,
+            CashierUserId = _svc.Session?.CashierUserId,
+            RetailPointId = CurrentShift?.RetailPointId ?? _svc.Session?.RetailPointId,
+            CashShiftId = CurrentShift?.Id,
+            IsReturn = true, ReferenceSaleId = referenceSaleId,
+            Payment = (int)method, PaidCash = refundCash, PaidCard = refundCard,
+            Lines = lines,
+        };
+        _svc.Store.EnqueueSale(sale);
+
+        bool printed = false; string? printErr = null;
+        try { await _svc.Printer.PrintAsync(BuildReturnReceipt(lines, display, refundCash, refundCard), ct); printed = true; }
+        catch (Exception ex) { printErr = ex.Message; }
+
+        bool pushedNow = false;
+        if (_svc.Sync is not null)
+        {
+            try { var r = await _svc.Sync.PushSalesAsync(ct); pushedNow = r.Accepted > 0; }
+            catch { /* офлайн */ }
+        }
+        return new CommitResult(sale.ClientSaleId, pushedNow, _svc.Store.PendingCount(), printed, printErr);
+    }
+
+    private ReceiptDoc BuildReturnReceipt(IReadOnlyList<PosSaleLineDto> lines,
+        IReadOnlyList<(string Name, string Unit)> display, decimal refundCash, decimal refundCard)
+    {
+        var doc = new ReceiptDoc { Title = "ВОЗВРАТ" };
+        doc.Add("Food Market", center: true, bold: true);
+        if (CurrentShift?.Number is { } sn) doc.Add($"Смена {sn}", center: true);
+        if (_svc.Session?.CashierName is { } c) doc.Add($"Кассир: {c}");
+        doc.Add(DateTime.Now.ToString("dd.MM.yyyy HH:mm:ss"));
+        doc.Separator();
+        decimal total = 0m;
+        for (int i = 0; i < lines.Count; i++)
+        {
+            var l = lines[i];
+            var name = i < display.Count ? display[i].Name : l.ProductId.ToString();
+            var unit = i < display.Count ? display[i].Unit : "шт";
+            var lineTotal = decimal.Round(l.Quantity * l.UnitPrice, 2);
+            total += lineTotal;
+            doc.Add(name);
+            doc.Add($"  {l.Quantity:0.###} {unit} x {l.UnitPrice:N0}", $"{lineTotal:N0}");
+        }
+        doc.Separator();
+        doc.Add("К ВОЗВРАТУ", $"{total:N0} ₸", bold: true, big: true);
+        if (refundCash > 0m) doc.Add("Наличными", $"{refundCash:N0}");
+        if (refundCard > 0m) doc.Add("На карту", $"{refundCard:N0}");
+        doc.Separator();
+        return doc;
+    }
+
     private ReceiptDoc BuildReceipt(Cart cart, decimal paidCash, decimal paidCard, decimal change, bool isReturn)
     {
         var t = cart.Totals();
diff --git a/src/food-market.pos/ViewModels/ViewModels.cs b/src/food-market.pos/ViewModels/ViewModels.cs
index aace038..baa6468 100644
--- a/src/food-market.pos/ViewModels/ViewModels.cs
+++ b/src/food-market.pos/ViewModels/ViewModels.cs
@@ -529,34 +529,109 @@ private async Task DrawerAsync(int direction, decimal amount, string reason)
     public static ShiftViewModel SampleClosed() { var s = new ShiftViewModel { IsOpen = false }; return s; }
 }
 
+/// <summary>Строка возврата: сколько продано/уже возвращено и сколько кассир
+/// выбирает к возврату (0..ReturnableQty).</summary>
+public partial class ReturnLineVm : ObservableObject
+{
+    public required Guid ProductId { get; init; }
+    [ObservableProperty] private string _name = "";
+    [ObservableProperty] private string _unit = "шт";
+    [ObservableProperty] private decimal _unitPrice;
+    [ObservableProperty] private decimal _soldQty;
+    [ObservableProperty] private decimal _returnableQty;
+    [ObservableProperty] private decimal _qty;
+    public decimal LineRefund => decimal.Round(UnitPrice * Qty, 2);
+    public string QtyText => Qty == decimal.Truncate(Qty) && Unit == "шт" ? Qty.ToString("0") : Qty.ToString("0.###");
+    public string AvailText => $"доступно к возврату: {(ReturnableQty == decimal.Truncate(ReturnableQty) ? ReturnableQty.ToString("0") : ReturnableQty.ToString("0.###"))} {Unit}";
+    partial void OnQtyChanged(decimal value) { OnPropertyChanged(nameof(LineRefund)); OnPropertyChanged(nameof(QtyText)); }
+}
+
+/// <summary>Возврат по чеку: найти чек (номер/скан QR), отметить позиции и
+/// количество (не больше проданного минус уже возвращённого), сумма к выдаче,
+/// способ (нал/карта как в исходном чеке).</summary>
 public partial class ReturnViewModel : ViewModelBase
 {
     private readonly AppServices? _svc;
     [ObservableProperty] private string _receiptNumber = "";
     [ObservableProperty] private string _message = "Отсканируйте QR чека или введите номер";
     [ObservableProperty] private bool _busy;
-    public ObservableCollection<SaleLineVm> Lines { get; } = new();
-    public decimal RefundTotal => Lines.Sum(l => l.LineTotal);
+    [ObservableProperty] private bool _found;
+    private Guid? _saleId;
+    private int _payment; // способ оплаты исходного чека (0=нал,1=карта,…)
+
+    public ObservableCollection<ReturnLineVm> Lines { get; } = new();
+    public decimal RefundTotal => Lines.Sum(l => l.LineRefund);
+    public Action<CheckoutService.CommitResult>? ReturnCommitted;
 
     public ReturnViewModel() { }
     public ReturnViewModel(AppServices svc) { _svc = svc; }
 
     [RelayCommand]
-    private Task Lookup()
+    private async Task Lookup()
     {
-        // Возврат по чеку: поиск чека-основания по номеру/QR. Серверный разбор
-        // чека выполняется при проведении возврата; здесь — заготовка для
-        // интерактивного выбора позиций (полный UI выбора — вне MVP-задачи).
-        if (string.IsNullOrWhiteSpace(ReceiptNumber)) { Message = "Введите номер чека или отсканируйте QR"; return Task.CompletedTask; }
-        Message = $"Чек {ReceiptNumber}: отметьте возвращаемые позиции и подтвердите возврат";
-        return Task.CompletedTask;
+        var number = ReceiptNumber.Trim();
+        if (number.Length == 0) { Message = "Введите номер чека или отсканируйте QR"; return; }
+        if (_svc?.Api is null) { Message = "Нет связи с сервером"; return; }
+        Busy = true; Found = false; Lines.Clear();
+        try
+        {
+            var r = await _svc.Api.ReturnLookupAsync(number);
+            _saleId = r.SaleId; _payment = r.Payment;
+            foreach (var l in r.Lines.Where(x => x.ReturnableQty > 0))
+                Lines.Add(new ReturnLineVm
+                {
+                    ProductId = l.ProductId, Name = l.Name, Unit = l.UnitCode,
+                    UnitPrice = l.UnitPrice, SoldQty = l.SoldQty, ReturnableQty = l.ReturnableQty, Qty = 0m,
+                });
+            OnPropertyChanged(nameof(RefundTotal));
+            Found = Lines.Count > 0;
+            Message = Found
+                ? $"Чек {r.Number} найден — отметьте позиции к возврату"
+                : $"Чек {r.Number}: все позиции уже возвращены";
+        }
+        catch (Refit.ApiException ex) when (ex.StatusCode == System.Net.HttpStatusCode.NotFound)
+        { Message = "Чек не найден или не проведён"; }
+        catch (Exception ex) { Message = "Ошибка поиска: " + ex.Message; }
+        finally { Busy = false; }
+    }
+
+    [RelayCommand] private void Inc(ReturnLineVm l) { if (l.Qty < l.ReturnableQty) { l.Qty = Math.Min(l.ReturnableQty, l.Qty + 1m); OnPropertyChanged(nameof(RefundTotal)); } }
+    [RelayCommand] private void Dec(ReturnLineVm l) { if (l.Qty > 0) { l.Qty = Math.Max(0m, l.Qty - 1m); OnPropertyChanged(nameof(RefundTotal)); } }
+    [RelayCommand] private void Full(ReturnLineVm l) { l.Qty = l.ReturnableQty; OnPropertyChanged(nameof(RefundTotal)); }
+
+    [RelayCommand]
+    private async Task Submit()
+    {
+        if (_svc is null || _saleId is null) { Message = "Сначала найдите чек"; return; }
+        var chosen = Lines.Where(l => l.Qty > 0m).ToList();
+        if (chosen.Count == 0) { Message = "Отметьте хотя бы одну позицию к возврату"; return; }
+        Busy = true;
+        try
+        {
+            var lines = chosen.Select(l => new foodmarket.Shared.Pos.V1.PosSaleLineDto
+            { ProductId = l.ProductId, Quantity = l.Qty, UnitPrice = l.UnitPrice, Discount = 0m, VatPercent = 0m }).ToList();
+            var display = chosen.Select(l => (l.Name, l.Unit)).ToList();
+            var refund = RefundTotal;
+            var toCard = _payment == 1; // карта как в исходном чеке, иначе наличные
+            var res = await _svc.Checkout.CommitReturnAsync(lines, _saleId.Value,
+                refundCash: toCard ? 0m : refund, refundCard: toCard ? refund : 0m, display);
+            Message = res.PushedNow
+                ? $"Возврат оформлен — к выдаче {refund:N0} ₸"
+                : $"Возврат в очереди — к выдаче {refund:N0} ₸ (отправится при связи)";
+            Lines.Clear(); Found = false; _saleId = null; ReceiptNumber = "";
+            OnPropertyChanged(nameof(RefundTotal));
+            ReturnCommitted?.Invoke(res);
+        }
+        catch (Exception ex) { Message = "Не удалось оформить возврат: " + ex.Message; }
+        finally { Busy = false; }
     }
 
     public static ReturnViewModel Sample()
     {
-        var vm = new ReturnViewModel { ReceiptNumber = "Ч-2026-000128", Message = "Чек найден — отметьте возвращаемые позиции" };
-        vm.Lines.Add(new SaleLineVm { ProductId = Guid.NewGuid(), Name = "Молоко 2.5% 1л", Unit = "шт", Price = 450m, Quantity = 1 });
-        vm.Lines.Add(new SaleLineVm { ProductId = Guid.NewGuid(), Name = "Хлеб «Семейный»", Unit = "шт", Price = 280m, Quantity = 1 });
+        var vm = new ReturnViewModel { ReceiptNumber = "ПР-2026-000128", Message = "Чек найден — отметьте позиции к возврату", Found = true };
+        vm.Lines.Add(new ReturnLineVm { ProductId = Guid.NewGuid(), Name = "Молоко 2.5% 1л", Unit = "шт", UnitPrice = 450m, SoldQty = 2, ReturnableQty = 2, Qty = 1 });
+        vm.Lines.Add(new ReturnLineVm { ProductId = Guid.NewGuid(), Name = "Хлеб «Семейный» нарезной", Unit = "шт", UnitPrice = 280m, SoldQty = 1, ReturnableQty = 1, Qty = 1 });
+        vm.Lines.Add(new ReturnLineVm { ProductId = Guid.NewGuid(), Name = "Яблоки «Апорт» (вес)", Unit = "кг", UnitPrice = 690m, SoldQty = 1.235m, ReturnableQty = 1.235m, Qty = 0 });
         return vm;
     }
 }
diff --git a/src/food-market.pos/Views/ReturnView.axaml b/src/food-market.pos/Views/ReturnView.axaml
index 35ebb0b..4a22641 100644
--- a/src/food-market.pos/Views/ReturnView.axaml
+++ b/src/food-market.pos/Views/ReturnView.axaml
@@ -6,31 +6,50 @@
   <Grid Background="#0f172a" RowDefinitions="Auto,*,Auto" Margin="16">
     <StackPanel Grid.Row="0" Spacing="8">
       <TextBlock Text="Возврат по чеку" FontSize="22" FontWeight="Bold" Foreground="#f8fafc"/>
-      <Grid ColumnDefinitions="*,160">
-        <TextBox Classes="pos" Watermark="Номер чека или скан QR" Text="{Binding ReceiptNumber}"/>
-        <Button Grid.Column="1" Classes="pos" Margin="8,0,0,0" HorizontalAlignment="Stretch" Content="Найти" Command="{Binding LookupCommand}" IsDefault="True"/>
+      <Grid ColumnDefinitions="*,170">
+        <TextBox Classes="pos" Watermark="Номер чека или скан QR (Enter)" Text="{Binding ReceiptNumber}">
+          <TextBox.KeyBindings>
+            <KeyBinding Gesture="Enter" Command="{Binding LookupCommand}"/>
+          </TextBox.KeyBindings>
+        </TextBox>
+        <Button Grid.Column="1" Classes="pos" Margin="8,0,0,0" HorizontalAlignment="Stretch" Content="Найти" Command="{Binding LookupCommand}"/>
       </Grid>
-      <TextBlock Text="{Binding Message}" Foreground="#60a5fa"/>
+      <TextBlock Text="{Binding Message}" Foreground="#60a5fa" TextWrapping="Wrap"/>
     </StackPanel>
+
     <Border Grid.Row="1" Background="#111827" CornerRadius="10" Margin="0,10">
       <ListBox ItemsSource="{Binding Lines}" Background="Transparent" BorderThickness="0">
         <ListBox.ItemTemplate>
-          <DataTemplate x:DataType="vm:SaleLineVm">
-            <Grid ColumnDefinitions="Auto,*,120,120" Height="46">
-              <CheckBox IsChecked="True" VerticalAlignment="Center"/>
-              <TextBlock Grid.Column="1" Text="{Binding Name}" Foreground="#f3f4f6" FontSize="16" VerticalAlignment="Center"/>
-              <TextBlock Grid.Column="2" Text="{Binding Quantity, StringFormat='{}{0:0.###}'}" Foreground="#e5e7eb" HorizontalAlignment="Right" VerticalAlignment="Center"/>
-              <TextBlock Grid.Column="3" Text="{Binding LineTotal, StringFormat='{}{0:N0} ₸'}" Foreground="#fff" FontWeight="SemiBold" HorizontalAlignment="Right" VerticalAlignment="Center" Margin="0,0,10,0"/>
+          <DataTemplate x:DataType="vm:ReturnLineVm">
+            <Grid ColumnDefinitions="*,190,110,120" MinHeight="58">
+              <StackPanel VerticalAlignment="Center" Margin="4,6">
+                <TextBlock Text="{Binding Name}" Foreground="#f3f4f6" FontSize="16" TextWrapping="Wrap"/>
+                <TextBlock Text="{Binding AvailText}" Foreground="#94a3b8" FontSize="12.5"/>
+              </StackPanel>
+              <!-- Степпер количества к возврату -->
+              <StackPanel Grid.Column="1" Orientation="Horizontal" Spacing="6" HorizontalAlignment="Right" VerticalAlignment="Center">
+                <Button Classes="pos" Width="44" Height="40" Padding="0" FontSize="20" Content="−"
+                        Command="{Binding $parent[ItemsControl].((vm:ReturnViewModel)DataContext).DecCommand}" CommandParameter="{Binding}"/>
+                <Border Background="#0b1220" CornerRadius="6" Width="58" Height="40">
+                  <TextBlock Text="{Binding QtyText}" Foreground="#f8fafc" FontSize="17" HorizontalAlignment="Center" VerticalAlignment="Center"/>
+                </Border>
+                <Button Classes="pos" Width="44" Height="40" Padding="0" FontSize="20" Content="+"
+                        Command="{Binding $parent[ItemsControl].((vm:ReturnViewModel)DataContext).IncCommand}" CommandParameter="{Binding}"/>
+              </StackPanel>
+              <Button Grid.Column="2" Classes="pos" Height="40" FontSize="13" Margin="6,0,0,0" Content="Всё"
+                      Command="{Binding $parent[ItemsControl].((vm:ReturnViewModel)DataContext).FullCommand}" CommandParameter="{Binding}"/>
+              <TextBlock Grid.Column="3" Text="{Binding LineRefund, StringFormat='{}{0:N0} ₸'}" Foreground="#ffffff" FontWeight="SemiBold" FontSize="17" HorizontalAlignment="Right" VerticalAlignment="Center" Margin="0,0,10,0"/>
             </Grid>
           </DataTemplate>
         </ListBox.ItemTemplate>
       </ListBox>
     </Border>
+
     <Grid Grid.Row="2" ColumnDefinitions="*,Auto">
       <TextBlock Text="К возврату" Foreground="#cbd5e1" FontSize="18" VerticalAlignment="Center"/>
       <StackPanel Grid.Column="1" Orientation="Horizontal" Spacing="16">
-        <TextBlock Text="{Binding RefundTotal, StringFormat='{}{0:N0} ₸'}" Foreground="#fca5a5" FontSize="24" FontWeight="Bold" VerticalAlignment="Center"/>
-        <Button Classes="pos danger" Height="56" Content="Оформить возврат"/>
+        <TextBlock Text="{Binding RefundTotal, StringFormat='{}{0:N0} ₸'}" Foreground="#fca5a5" FontSize="26" FontWeight="Bold" VerticalAlignment="Center"/>
+        <Button Classes="pos danger" Height="56" Width="230" Content="Оформить возврат" Command="{Binding SubmitCommand}" IsEnabled="{Binding Found}"/>
       </StackPanel>
     </Grid>
   </Grid>
diff --git a/src/food-market.shared/Pos/V1/SyncDtos.cs b/src/food-market.shared/Pos/V1/SyncDtos.cs
index d579c1f..8966f38 100644
--- a/src/food-market.shared/Pos/V1/SyncDtos.cs
+++ b/src/food-market.shared/Pos/V1/SyncDtos.cs
@@ -183,3 +183,25 @@ public record PosSaleFailedDto
     public required string Error { get; init; }
     public string? Field { get; init; }
 }
+
+/// <summary>Чек-основание для возврата по номеру/QR: шапка + позиции с
+/// количеством, доступным к возврату (продано − уже возвращено).</summary>
+public record PosReturnLookupDto
+{
+    public required Guid SaleId { get; init; }
+    public required string Number { get; init; }
+    public required DateTime Date { get; init; }
+    public required int Payment { get; init; }      // PaymentMethod исходного чека
+    public required IReadOnlyList<PosReturnLineDto> Lines { get; init; }
+}
+
+public record PosReturnLineDto
+{
+    public required Guid ProductId { get; init; }
+    public required string Name { get; init; }
+    public required string UnitCode { get; init; }
+    public required decimal UnitPrice { get; init; }
+    public required decimal SoldQty { get; init; }
+    public required decimal ReturnedQty { get; init; }
+    public required decimal ReturnableQty { get; init; } // SoldQty − ReturnedQty
+}
diff --git a/tests/food-market.IntegrationTests/PosSyncTests.cs b/tests/food-market.IntegrationTests/PosSyncTests.cs
index 20dc519..4709282 100644
--- a/tests/food-market.IntegrationTests/PosSyncTests.cs
+++ b/tests/food-market.IntegrationTests/PosSyncTests.cs
@@ -304,6 +304,66 @@ private static async Task<string> OpenShiftAsync(ApiActor api, string retailPoin
         return JsonDocument.Parse(body).RootElement.GetProperty("id").GetString()!;
     }
 
+    /// <summary>Возврат по чеку через кассу: lookup by-number отдаёт доступное к
+    /// возврату; POS-возврат уважает остаток (нельзя вернуть больше проданного
+    /// минус уже возвращённого) и инкрементит QtyReturned.</summary>
+    [Fact]
+    public async Task Pos_return_by_receipt_respects_returnable_quantity()
+    {
+        var api = new ApiActor(_factory.CreateClient());
+        await api.SignupAndLoginAsync($"pos-retfull-{Guid.NewGuid():N}");
+        var refs = await api.LoadRefsAsync();
+        var p1 = await api.CreateProductAsync(refs, $"P-{Guid.NewGuid():N}", 100m, RandomBarcode());
+        await SeedStockAsync(api, refs, p1, 10m);
+
+        // Продажа 3 шт через кассу.
+        var saleBatch = new PosSaleBatchDto { IdempotencyKey = Guid.NewGuid(), Sales = new[] { MakeSale(p1, 3m, 100m) } };
+        var saleResp = await (await api.Http.PostAsJsonAsync("/api/pos/v1/sales", saleBatch)).Content.ReadFromJsonAsync<PosSaleBatchResponse>();
+        saleResp!.Accepted.Should().HaveCount(1);
+        var refId = saleResp.Accepted[0].ServerSaleId;
+        var number = saleResp.Accepted[0].ServerSaleNumber;
+        (await api.StockOfAsync(refs.StoreId, p1)).Should().Be(7m);
+
+        // Lookup по номеру → доступно к возврату 3.
+        var look = await api.Http.GetFromJsonAsync<PosReturnLookupDto>($"/api/pos/v1/sales/by-number/{number}");
+        look!.Lines.Should().ContainSingle();
+        look.Lines[0].SoldQty.Should().Be(3m);
+        look.Lines[0].ReturnedQty.Should().Be(0m);
+        look.Lines[0].ReturnableQty.Should().Be(3m);
+
+        // Возврат 2 шт → принят, остаток +2 = 9.
+        var ret1 = new PosSaleBatchDto { IdempotencyKey = Guid.NewGuid(), Sales = new[] { MakeSale(p1, 2m, 100m) with { IsReturn = true, ReferenceSaleId = refId } } };
+        (await (await api.Http.PostAsJsonAsync("/api/pos/v1/sales", ret1)).Content.ReadFromJsonAsync<PosSaleBatchResponse>())!.Accepted.Should().HaveCount(1);
+        (await api.StockOfAsync(refs.StoreId, p1)).Should().Be(9m);
+
+        // Теперь доступно к возврату 1.
+        var look2 = await api.Http.GetFromJsonAsync<PosReturnLookupDto>($"/api/pos/v1/sales/by-number/{number}");
+        look2!.Lines[0].ReturnedQty.Should().Be(2m);
+        look2.Lines[0].ReturnableQty.Should().Be(1m);
+
+        // Попытка вернуть ещё 2 (over-return) → в Failed, остаток не меняется.
+        var retOver = new PosSaleBatchDto { IdempotencyKey = Guid.NewGuid(), Sales = new[] { MakeSale(p1, 2m, 100m) with { IsReturn = true, ReferenceSaleId = refId } } };
+        var overResp = await (await api.Http.PostAsJsonAsync("/api/pos/v1/sales", retOver)).Content.ReadFromJsonAsync<PosSaleBatchResponse>();
+        overResp!.Accepted.Should().BeEmpty();
+        overResp.Failed.Should().ContainSingle();
+        overResp.Failed[0].Error.Should().Contain("больше, чем доступно");
+        (await api.StockOfAsync(refs.StoreId, p1)).Should().Be(9m);
+
+        // Возврат оставшейся 1 → принят, остаток 10.
+        var ret2 = new PosSaleBatchDto { IdempotencyKey = Guid.NewGuid(), Sales = new[] { MakeSale(p1, 1m, 100m) with { IsReturn = true, ReferenceSaleId = refId } } };
+        (await (await api.Http.PostAsJsonAsync("/api/pos/v1/sales", ret2)).Content.ReadFromJsonAsync<PosSaleBatchResponse>())!.Accepted.Should().HaveCount(1);
+        (await api.StockOfAsync(refs.StoreId, p1)).Should().Be(10m);
+    }
+
+    [Fact]
+    public async Task Pos_return_lookup_unknown_number_is_404()
+    {
+        var api = new ApiActor(_factory.CreateClient());
+        await api.SignupAndLoginAsync($"pos-ret404-{Guid.NewGuid():N}");
+        using var resp = await api.Http.GetAsync("/api/pos/v1/sales/by-number/ПР-2000-999999");
+        resp.StatusCode.Should().Be(System.Net.HttpStatusCode.NotFound);
+    }
+
     private static PosSaleDto MakeSale(string productId, decimal qty, decimal price) => new()
     {
         ClientSaleId = Guid.NewGuid(),
diff --git a/tests/food-market.UnitTests/PosCoreTests.cs b/tests/food-market.UnitTests/PosCoreTests.cs
index 63e7a13..0f92820 100644
--- a/tests/food-market.UnitTests/PosCoreTests.cs
+++ b/tests/food-market.UnitTests/PosCoreTests.cs
@@ -222,6 +222,7 @@ public Task<PosSaleBatchResponse> AcceptSalesAsync(PosSaleBatchDto batch, Cancel
         }
 
         public Task<PosVersionDto> VersionAsync(CancellationToken ct = default) => throw new NotImplementedException();
+        public Task<PosReturnLookupDto> ReturnLookupAsync(string number, CancellationToken ct = default) => throw new NotImplementedException();
         public Task<PosSyncResponse> SyncAsync(DateTime? since, CancellationToken ct = default) => throw new NotImplementedException();
         public Task<MeDto> MeAsync(CancellationToken ct = default) => throw new NotImplementedException();
         public Task<PagedDto<RetailPointDto>> RetailPointsAsync(int pageSize = 200, CancellationToken ct = default) => throw new NotImplementedException();