feat: add LetterXpress (A&O Fischer) API v3 carrier

.github/workflows/ci.yml

@@ -58,6 +58,9 @@ jobs:
       - name: Test - GoExpress.Shipping
         run: dotnet test tests/Parcel.NET.GoExpress.Shipping.Tests/Parcel.NET.GoExpress.Shipping.Tests.csproj -c Release --no-build -f ${{ matrix.target-framework }}
 
+      - name: Test - LetterXpress.Letters
+        run: dotnet test tests/Parcel.NET.LetterXpress.Letters.Tests/Parcel.NET.LetterXpress.Letters.Tests.csproj -c Release --no-build -f ${{ matrix.target-framework }}
+
       - name: Check for vulnerable packages
         if: matrix.target-framework == 'net10.0'
         run: |
@@ -117,3 +120,4 @@ jobs:
           check_changes "src/Parcel.NET.Abstractions/" "abstractions" "Parcel.NET.Abstractions"
           check_changes "src/Parcel.NET.Dhl/" "dhl" "Parcel.NET.Dhl"
           check_changes "src/Parcel.NET.GoExpress/" "goexpress" "Parcel.NET.GoExpress"
+          check_changes "src/Parcel.NET.LetterXpress/" "letterxpress" "Parcel.NET.LetterXpress"

.github/workflows/create-release-tag.yml

@@ -20,8 +20,11 @@ on:
           - goexpress
           - goexpress-shipping
           - goexpress-tracking
+          - letterxpress
+          - letterxpress-letters
           - dhl-all
           - goexpress-all
+          - letterxpress-all
           - all
       version:
         description: 'SemVer version (without v prefix, e.g. 1.0.0)'

.github/workflows/release-letterxpress-all.yml

@@ -0,0 +1,19 @@
+name: Release Parcel.NET.LetterXpress.All
+
+on:
+  push:
+    tags: ['letterxpress-all/v*']
+  workflow_dispatch:
+
+permissions:
+  contents: write
+
+jobs:
+  release:
+    uses: ./.github/workflows/release-package.yml
+    with:
+      package: 'letterxpress-all'
+      csproj-path: 'src/Parcel.NET.LetterXpress.All/Parcel.NET.LetterXpress.All.csproj'
+      title-prefix: 'Parcel.NET.LetterXpress.All'
+    secrets:
+      nuget-api-key: ${{ secrets.NUGET_API_KEY }}

.github/workflows/release-letterxpress-letters.yml

@@ -0,0 +1,19 @@
+name: Release Parcel.NET.LetterXpress.Letters
+
+on:
+  push:
+    tags: ['letterxpress-letters/v*']
+  workflow_dispatch:
+
+permissions:
+  contents: write
+
+jobs:
+  release:
+    uses: ./.github/workflows/release-package.yml
+    with:
+      package: 'letterxpress-letters'
+      csproj-path: 'src/Parcel.NET.LetterXpress.Letters/Parcel.NET.LetterXpress.Letters.csproj'
+      title-prefix: 'Parcel.NET.LetterXpress.Letters'
+    secrets:
+      nuget-api-key: ${{ secrets.NUGET_API_KEY }}

.github/workflows/release-letterxpress.yml

@@ -0,0 +1,19 @@
+name: Release Parcel.NET.LetterXpress
+
+on:
+  push:
+    tags: ['letterxpress/v*']
+  workflow_dispatch:
+
+permissions:
+  contents: write
+
+jobs:
+  release:
+    uses: ./.github/workflows/release-package.yml
+    with:
+      package: 'letterxpress'
+      csproj-path: 'src/Parcel.NET.LetterXpress/Parcel.NET.LetterXpress.csproj'
+      title-prefix: 'Parcel.NET.LetterXpress'
+    secrets:
+      nuget-api-key: ${{ secrets.NUGET_API_KEY }}

Parcel.NET.slnx

@@ -1,37 +1,41 @@
-<Solution>
-  <Folder Name="/docs/">
-    <Project Path="docs/Parcel.NET.Docs/Parcel.NET.Docs.csproj" />
-    <Project Path="docs/Parcel.NET.Docs.Generator/Parcel.NET.Docs.Generator.csproj" />
-  </Folder>
-  <Folder Name="/samples/">
-    <Project Path="samples/Parcel.NET.Samples.Console/Parcel.NET.Samples.Console.csproj" />
-  </Folder>
-  <Folder Name="/src/">
-    <Project Path="src/Parcel.NET.Abstractions/Parcel.NET.Abstractions.csproj" />
-    <Project Path="src/Parcel.NET.Dhl/Parcel.NET.Dhl.csproj" />
-    <Project Path="src/Parcel.NET.Dhl.Shipping/Parcel.NET.Dhl.Shipping.csproj" />
-    <Project Path="src/Parcel.NET.Dhl.Tracking/Parcel.NET.Dhl.Tracking.csproj" />
-    <Project Path="src/Parcel.NET.Dhl.UnifiedTracking/Parcel.NET.Dhl.UnifiedTracking.csproj" />
-    <Project Path="src/Parcel.NET.Dhl.Pickup/Parcel.NET.Dhl.Pickup.csproj" />
-    <Project Path="src/Parcel.NET.Dhl.Returns/Parcel.NET.Dhl.Returns.csproj" />
-    <Project Path="src/Parcel.NET.Dhl.Internetmarke/Parcel.NET.Dhl.Internetmarke.csproj" />
-    <Project Path="src/Parcel.NET.Dhl.LocationFinder/Parcel.NET.Dhl.LocationFinder.csproj" />
-    <Project Path="src/Parcel.NET.GoExpress/Parcel.NET.GoExpress.csproj" />
-    <Project Path="src/Parcel.NET.GoExpress.Shipping/Parcel.NET.GoExpress.Shipping.csproj" />
-    <Project Path="src/Parcel.NET.GoExpress.Tracking/Parcel.NET.GoExpress.Tracking.csproj" />
-    <Project Path="src/Parcel.NET.Dhl.All/Parcel.NET.Dhl.All.csproj" />
-    <Project Path="src/Parcel.NET.GoExpress.All/Parcel.NET.GoExpress.All.csproj" />
-    <Project Path="src/Parcel.NET.All/Parcel.NET.All.csproj" />
-  </Folder>
-  <Folder Name="/tests/">
-    <Project Path="tests/Parcel.NET.Dhl.Shipping.Tests/Parcel.NET.Dhl.Shipping.Tests.csproj" />
-    <Project Path="tests/Parcel.NET.Dhl.Tracking.Tests/Parcel.NET.Dhl.Tracking.Tests.csproj" />
-    <Project Path="tests/Parcel.NET.Dhl.UnifiedTracking.Tests/Parcel.NET.Dhl.UnifiedTracking.Tests.csproj" />
-    <Project Path="tests/Parcel.NET.Dhl.Pickup.Tests/Parcel.NET.Dhl.Pickup.Tests.csproj" />
-    <Project Path="tests/Parcel.NET.Dhl.Returns.Tests/Parcel.NET.Dhl.Returns.Tests.csproj" />
-    <Project Path="tests/Parcel.NET.Dhl.Internetmarke.Tests/Parcel.NET.Dhl.Internetmarke.Tests.csproj" />
-    <Project Path="tests/Parcel.NET.Dhl.LocationFinder.Tests/Parcel.NET.Dhl.LocationFinder.Tests.csproj" />
-    <Project Path="tests/Parcel.NET.GoExpress.Shipping.Tests/Parcel.NET.GoExpress.Shipping.Tests.csproj" />
-    <Project Path="tests/Parcel.NET.GoExpress.Tracking.Tests/Parcel.NET.GoExpress.Tracking.Tests.csproj" />
-  </Folder>
-</Solution>
+<Solution>
+  <Folder Name="/docs/">
+    <Project Path="docs/Parcel.NET.Docs/Parcel.NET.Docs.csproj" />
+    <Project Path="docs/Parcel.NET.Docs.Generator/Parcel.NET.Docs.Generator.csproj" />
+  </Folder>
+  <Folder Name="/samples/">
+    <Project Path="samples/Parcel.NET.Samples.Console/Parcel.NET.Samples.Console.csproj" />
+  </Folder>
+  <Folder Name="/src/">
+    <Project Path="src/Parcel.NET.Abstractions/Parcel.NET.Abstractions.csproj" />
+    <Project Path="src/Parcel.NET.Dhl/Parcel.NET.Dhl.csproj" />
+    <Project Path="src/Parcel.NET.Dhl.Shipping/Parcel.NET.Dhl.Shipping.csproj" />
+    <Project Path="src/Parcel.NET.Dhl.Tracking/Parcel.NET.Dhl.Tracking.csproj" />
+    <Project Path="src/Parcel.NET.Dhl.UnifiedTracking/Parcel.NET.Dhl.UnifiedTracking.csproj" />
+    <Project Path="src/Parcel.NET.Dhl.Pickup/Parcel.NET.Dhl.Pickup.csproj" />
+    <Project Path="src/Parcel.NET.Dhl.Returns/Parcel.NET.Dhl.Returns.csproj" />
+    <Project Path="src/Parcel.NET.Dhl.Internetmarke/Parcel.NET.Dhl.Internetmarke.csproj" />
+    <Project Path="src/Parcel.NET.Dhl.LocationFinder/Parcel.NET.Dhl.LocationFinder.csproj" />
+    <Project Path="src/Parcel.NET.GoExpress/Parcel.NET.GoExpress.csproj" />
+    <Project Path="src/Parcel.NET.GoExpress.Shipping/Parcel.NET.GoExpress.Shipping.csproj" />
+    <Project Path="src/Parcel.NET.GoExpress.Tracking/Parcel.NET.GoExpress.Tracking.csproj" />
+    <Project Path="src/Parcel.NET.LetterXpress/Parcel.NET.LetterXpress.csproj" />
+    <Project Path="src/Parcel.NET.LetterXpress.Letters/Parcel.NET.LetterXpress.Letters.csproj" />
+    <Project Path="src/Parcel.NET.Dhl.All/Parcel.NET.Dhl.All.csproj" />
+    <Project Path="src/Parcel.NET.GoExpress.All/Parcel.NET.GoExpress.All.csproj" />
+    <Project Path="src/Parcel.NET.LetterXpress.All/Parcel.NET.LetterXpress.All.csproj" />
+    <Project Path="src/Parcel.NET.All/Parcel.NET.All.csproj" />
+  </Folder>
+  <Folder Name="/tests/">
+    <Project Path="tests/Parcel.NET.Dhl.Shipping.Tests/Parcel.NET.Dhl.Shipping.Tests.csproj" />
+    <Project Path="tests/Parcel.NET.Dhl.Tracking.Tests/Parcel.NET.Dhl.Tracking.Tests.csproj" />
+    <Project Path="tests/Parcel.NET.Dhl.UnifiedTracking.Tests/Parcel.NET.Dhl.UnifiedTracking.Tests.csproj" />
+    <Project Path="tests/Parcel.NET.Dhl.Pickup.Tests/Parcel.NET.Dhl.Pickup.Tests.csproj" />
+    <Project Path="tests/Parcel.NET.Dhl.Returns.Tests/Parcel.NET.Dhl.Returns.Tests.csproj" />
+    <Project Path="tests/Parcel.NET.Dhl.Internetmarke.Tests/Parcel.NET.Dhl.Internetmarke.Tests.csproj" />
+    <Project Path="tests/Parcel.NET.Dhl.LocationFinder.Tests/Parcel.NET.Dhl.LocationFinder.Tests.csproj" />
+    <Project Path="tests/Parcel.NET.GoExpress.Shipping.Tests/Parcel.NET.GoExpress.Shipping.Tests.csproj" />
+    <Project Path="tests/Parcel.NET.GoExpress.Tracking.Tests/Parcel.NET.GoExpress.Tracking.Tests.csproj" />
+    <Project Path="tests/Parcel.NET.LetterXpress.Letters.Tests/Parcel.NET.LetterXpress.Letters.Tests.csproj" />
+  </Folder>
+</Solution>

README.md

@@ -4,7 +4,7 @@
 
 # Parcel.NET
 
-.NET libraries for logistics carrier APIs. Currently supports **DHL** (Shipping, Tracking, Pickup, Returns, Internetmarke, Location Finder) and **GO! Express** (Shipping, Tracking) — all targeting .NET 8, 9, and 10.
+.NET libraries for logistics carrier APIs. Currently supports **DHL** (Shipping, Tracking, Pickup, Returns, Internetmarke, Location Finder), **GO! Express** (Shipping, Tracking), and **LetterXpress** (Letters / SMART@MAIL) — all targeting .NET 8, 9, and 10.
 
 [![CI](https://github.com/emuuu/Parcel.NET/actions/workflows/ci.yml/badge.svg)](https://github.com/emuuu/Parcel.NET/actions/workflows/ci.yml)
 [![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](LICENSE)
@@ -21,9 +21,10 @@
 - DHL Unified Location Finder v1 — search by address, geo-coordinates, or keyword
 - GO! Express Shipping — create, cancel shipments, label generation
 - GO! Express Tracking — track shipments
+- LetterXpress API v3 — print jobs, SMART@MAIL e-mail jobs, balance, price, transactions, invoices
 - Builder-pattern DI registration with typed `HttpClient` pipeline
 - OAuth ROPC, API key, and Basic Auth — handled automatically per carrier
-- Sandbox support for DHL and GO! Express
+- Sandbox / test mode support for DHL, GO! Express, and LetterXpress
 
 ## Packages
 
@@ -43,15 +44,19 @@
 | `Parcel.NET.GoExpress` | [![NuGet](https://img.shields.io/nuget/v/Parcel.NET.GoExpress.svg)](https://www.nuget.org/packages/Parcel.NET.GoExpress) | GO! Express authentication, configuration, and DI extensions |
 | `Parcel.NET.GoExpress.Shipping` | [![NuGet](https://img.shields.io/nuget/v/Parcel.NET.GoExpress.Shipping.svg)](https://www.nuget.org/packages/Parcel.NET.GoExpress.Shipping) | GO! Express Shipping client |
 | `Parcel.NET.GoExpress.Tracking` | [![NuGet](https://img.shields.io/nuget/v/Parcel.NET.GoExpress.Tracking.svg)](https://www.nuget.org/packages/Parcel.NET.GoExpress.Tracking) | GO! Express Tracking client |
+| **LetterXpress** | | |
+| `Parcel.NET.LetterXpress` | [![NuGet](https://img.shields.io/nuget/v/Parcel.NET.LetterXpress.svg)](https://www.nuget.org/packages/Parcel.NET.LetterXpress) | LetterXpress authentication, configuration, and DI extensions |
+| `Parcel.NET.LetterXpress.Letters` | [![NuGet](https://img.shields.io/nuget/v/Parcel.NET.LetterXpress.Letters.svg)](https://www.nuget.org/packages/Parcel.NET.LetterXpress.Letters) | LetterXpress API v3 client (print jobs, SMART@MAIL e-mail jobs, price, balance, transactions, invoices) |
 | **Meta-Packages** | | |
 | `Parcel.NET.Dhl.All` | [![NuGet](https://img.shields.io/nuget/v/Parcel.NET.Dhl.All.svg)](https://www.nuget.org/packages/Parcel.NET.Dhl.All) | All DHL packages |
 | `Parcel.NET.GoExpress.All` | [![NuGet](https://img.shields.io/nuget/v/Parcel.NET.GoExpress.All.svg)](https://www.nuget.org/packages/Parcel.NET.GoExpress.All) | All GO! Express packages |
+| `Parcel.NET.LetterXpress.All` | [![NuGet](https://img.shields.io/nuget/v/Parcel.NET.LetterXpress.All.svg)](https://www.nuget.org/packages/Parcel.NET.LetterXpress.All) | All LetterXpress packages |
 | `Parcel.NET.All` | [![NuGet](https://img.shields.io/nuget/v/Parcel.NET.All.svg)](https://www.nuget.org/packages/Parcel.NET.All) | All Parcel.NET packages |
 
 ## Prerequisites
 
 - .NET 8.0, 9.0, or 10.0
-- A DHL developer account and/or GO! Express credentials
+- A DHL developer account, GO! Express credentials, and/or a LetterXpress account
 
 ## Installation
 
@@ -60,10 +65,12 @@
 dotnet add package Parcel.NET.Dhl.Shipping
 dotnet add package Parcel.NET.Dhl.Tracking
 dotnet add package Parcel.NET.GoExpress.Shipping
+dotnet add package Parcel.NET.LetterXpress.Letters
 
 # Or install everything for a carrier
 dotnet add package Parcel.NET.Dhl.All
 dotnet add package Parcel.NET.GoExpress.All
+dotnet add package Parcel.NET.LetterXpress.All
 
 # Or install all carriers at once
 dotnet add package Parcel.NET.All
@@ -106,6 +113,41 @@ builder.Services.AddGoExpress(options =>
 .AddGoExpressTracking();
 ```
 
+### 2b. Register LetterXpress services
+
+```csharp
+builder.Services.AddLetterXpress(options =>
+{
+    options.Username = "your-username";
+    options.ApiKey = "your-api-key";
+    options.UseTestMode = true; // jobs go to the Postbox instead of being processed
+})
+.AddLetterXpressLetters();
+```
+
+Send a letter as a print job:
+
+```csharp
+var letterXpress = serviceProvider.GetRequiredService<ILetterXpressClient>();
+
+var balance = await letterXpress.GetBalanceAsync();
+
+var job = await letterXpress.CreatePrintJobAsync(new LetterRequest
+{
+    File = await File.ReadAllBytesAsync("invoice.pdf"),
+    Specification = new LetterSpecification
+    {
+        Color = LetterColor.BlackWhite,
+        Mode = PrintMode.Simplex,
+        Shipping = ShippingType.National
+    }
+});
+```
+
+> **Note:** The LetterXpress API is rate-limited to 120 requests/minute and accepts at most 50 MB per request.
+> The client validates the 50 MB limit locally; throttling/retry on HTTP 429 is left to the caller's `HttpClient`
+> pipeline (e.g. a `Microsoft.Extensions.Http.Resilience` handler).
+
 ### 3. Create a shipment
 
 Use the carrier-agnostic `IShipmentService` or the carrier-specific client:

docs/Parcel.NET.Docs.Generator/Parcel.NET.Docs.Generator.csproj

@@ -21,6 +21,8 @@
     <ProjectReference Include="../../src/Parcel.NET.Dhl.Tracking/Parcel.NET.Dhl.Tracking.csproj" />
     <ProjectReference Include="../../src/Parcel.NET.GoExpress/Parcel.NET.GoExpress.csproj" />
     <ProjectReference Include="../../src/Parcel.NET.GoExpress.Shipping/Parcel.NET.GoExpress.Shipping.csproj" />
+    <ProjectReference Include="../../src/Parcel.NET.LetterXpress/Parcel.NET.LetterXpress.csproj" />
+    <ProjectReference Include="../../src/Parcel.NET.LetterXpress.Letters/Parcel.NET.LetterXpress.Letters.csproj" />
   </ItemGroup>
 
 </Project>

docs/Parcel.NET.Docs.Generator/Program.cs

@@ -103,7 +103,9 @@ async Task GenerateApiDocs(string wwwrootPath)
         typeof(Parcel.NET.Dhl.Shipping.IDhlShippingClient).Assembly,
         typeof(Parcel.NET.Dhl.Tracking.DhlTrackingClient).Assembly,
         typeof(Parcel.NET.GoExpress.GoExpressOptions).Assembly,
-        typeof(Parcel.NET.GoExpress.Shipping.IGoExpressShippingClient).Assembly
+        typeof(Parcel.NET.GoExpress.Shipping.IGoExpressShippingClient).Assembly,
+        typeof(Parcel.NET.LetterXpress.LetterXpressOptions).Assembly,
+        typeof(Parcel.NET.LetterXpress.Letters.ILetterXpressClient).Assembly
     };
 
     var xmlDocs = new Dictionary<string, XDocument>();