mailpit-integration

1# Email Testing with Mailpit and .NET Aspire
2 
3## When to Use This Skill
4 
5Use this skill when:
6- Testing email delivery locally without sending real emails
7- Setting up email infrastructure in .NET Aspire
8- Writing integration tests that verify emails are sent
9- Debugging email rendering and headers
10 
11**Related skills:**
12- `aspnetcore/mjml-email-templates` - MJML template authoring
13- `testing/verify-email-snapshots` - Snapshot test rendered HTML
14- `aspire/integration-testing` - General Aspire testing patterns
15 
16---
17 
18## What is Mailpit?
19 
20[Mailpit](https://github.com/axllent/mailpit) is a lightweight email testing tool that:
21- Captures all SMTP traffic without delivering emails
22- Provides a web UI to view captured emails
23- Exposes an API for programmatic access
24- Supports HTML rendering, headers, and attachments
25 
26Perfect for development and integration testing.
27 
28---
29 
30## Aspire AppHost Configuration
31 
32Add Mailpit as a container in your AppHost:
33 
34```csharp
35// AppHost/Program.cs
36var builder = DistributedApplication.CreateBuilder(args);
37 
38// Add Mailpit for email testing
39var mailpit = builder.AddContainer("mailpit", "axllent/mailpit")
40    .WithHttpEndpoint(port: 8025, targetPort: 8025, name: "ui")
41    .WithEndpoint(port: 1025, targetPort: 1025, name: "smtp");
42 
43// Reference in your API project
44var api = builder.AddProject<Projects.MyApp_Api>("api")
45    .WithReference(mailpit.GetEndpoint("smtp"))
46    .WithEnvironment("Smtp__Host", mailpit.GetEndpoint("smtp"));
47 
48builder.Build().Run();
49```
50…