Mailpit Integration

This gets Mailpit wired up with .NET Aspire so you can test email flows without actually sending messages. It's the kind of thing you drop into your dev environment when you need to verify registration emails, password resets, or notification logic without touching a real SMTP server. Aaron's packaged it with clear guidance on when to reach for it versus related skills like MJML templating or snapshot testing. The integration testing angle is solid. It's a focused tool that does one thing well, and the 229 installs suggest people are finding it when they need it.

skills.sh installs: 443
GitHub stars: 1.3K
last updated: Aug 21, 2026

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Install

$ npx -y skills add aaronontheweb/dotnet-skills --skill mailpit-integration --agent claude-code

Installs into .claude/skills of the current project.

Files

Email Testing with Mailpit and .NET Aspire

When to Use This Skill

Use this skill when:

Testing email delivery locally without sending real emails
Setting up email infrastructure in .NET Aspire
Writing integration tests that verify emails are sent
Debugging email rendering and headers

Related skills:

aspnetcore/mjml-email-templates - MJML template authoring
testing/verify-email-snapshots - Snapshot test rendered HTML
aspire/integration-testing - General Aspire testing patterns

What is Mailpit?

Mailpit is a lightweight email testing tool that:

Captures all SMTP traffic without delivering emails
Provides a web UI to view captured emails
Exposes an API for programmatic access
Supports HTML rendering, headers, and attachments

Perfect for development and integration testing.

Aspire AppHost Configuration

Add Mailpit as a container in your AppHost:

// AppHost/Program.cs
var builder = DistributedApplication.CreateBuilder(args);

SKILL.md on GitHub

Details

Repository: github.com/aaronontheweb/dotnet-skills
Categories: Frontend Development, Testing & QA, .NET & C#
First seen: Jun 3, 2026