MailHog vs Mailpit vs Mailtrap: Email Testing Tools Compared (2026)

Why Email Testing Needs a Dedicated Tool

Testing email in a web application is surprisingly hard. You can't just hit send and check your inbox—that would send real emails to real users during test runs, leak test data, and make assertions impossible (how do you check the inbox programmatically?).

The standard solution is a fake SMTP server: configure your app to send to localhost:2525, and the fake server catches everything without forwarding it anywhere. You then query the server's API to assert on what was sent.

Three tools dominate this space: MailHog, Mailpit, and Mailtrap. They all solve the same core problem but with different tradeoffs.

MailHog

Status: Archived (last commit 2020), still widely used

MailHog is a Go binary that runs a fake SMTP server on port 1025 and a web UI on port 8025. It captures all incoming email and exposes a simple HTTP API for querying messages.

# Docker
docker run -d -p 1025:1025 -p 8025:8025 mailhog/mailhog

<span class="hljs-comment"># Or download the binary
wget https://github.com/mailhog/MailHog/releases/download/v1.0.1/MailHog_linux_amd64
<span class="hljs-built_in">chmod +x MailHog_linux_amd64
./MailHog_linux_amd64

API:

# List messages
curl http://localhost:8025/api/v2/messages

<span class="hljs-comment"># Delete all messages
curl -X DELETE http://localhost:8025/api/v1/messages

What MailHog does well:

• Extremely simple to set up
• Minimal resource footprint
• Wide language/framework support (every major language has a MailHog how-to)
• Web UI works fine for manual inspection

What MailHog lacks:

• No ARM64 support (the Docker image doesn't run natively on M1/M2 Macs)
• No spam analysis
• No HTML rendering preview
• No attachment download
• No longer maintained (security vulnerabilities won't be patched)
• API is bare-bones (v2 API returns paginated messages only)

Best for: Legacy projects, quick local testing where you don't need assertions, teams that have already standardized on it.

Mailpit

Status: Actively maintained, v1.x

Mailpit is a drop-in MailHog replacement written in Go. It has native ARM64 support, a modern UI, a proper REST API, and active development. If you're starting fresh or replacing MailHog, Mailpit is the better choice.

# Docker
docker run -d -p 1025:1025 -p 8025:8025 axllent/mailpit

<span class="hljs-comment"># Homebrew (Mac)
brew install mailpit

<span class="hljs-comment"># Binary download
curl -sL https://raw.githubusercontent.com/axllent/mailpit/develop/install.sh <span class="hljs-pipe">| bash

API:

# List messages
curl http://localhost:8025/api/v1/messages

<span class="hljs-comment"># Get single message with full content
curl http://localhost:8025/api/v1/message/{<span class="hljs-built_in">id}

<span class="hljs-comment"># Get rendered HTML
curl http://localhost:8025/api/v1/message/{<span class="hljs-built_in">id}/body.html

<span class="hljs-comment"># Delete all messages
curl -X DELETE http://localhost:8025/api/v1/messages

What Mailpit does well:

• ARM64 native (M1/M2 Mac, Raspberry Pi)
• Clean JSON API with full message content
• Attachment support with download
• HTML rendering preview
• Search functionality
• WebSocket push for real-time test notifications
• Active development and security patches
• Docker Compose-friendly

What Mailpit lacks:

• Spam score analysis
• Cloud-hosted option (local only)
• No team collaboration features

Best for: Local development, Docker Compose test environments, modern teams replacing MailHog.

Mailtrap

Status: Commercial SaaS, actively developed

Mailtrap is a cloud-hosted email testing service. Unlike MailHog and Mailpit, it runs on Mailtrap's servers—you configure your app to send to sandbox.smtp.mailtrap.io, and emails land in your Mailtrap inbox accessible from any browser.

// Nodemailer config
const transporter = nodemailer.createTransport({
  host: 'sandbox.smtp.mailtrap.io',
  port: 2525,
  auth: {
    user: process.env.MAILTRAP_USER,
    pass: process.env.MAILTRAP_PASS,
  },
});

API:

# List messages
curl -H <span class="hljs-string">"Api-Token: $TOKEN" https://mailtrap.io/api/inboxes/<span class="hljs-variable">$INBOX_ID/messages

<span class="hljs-comment"># Get HTML body
curl -H <span class="hljs-string">"Api-Token: $TOKEN" https://mailtrap.io/api/inboxes/<span class="hljs-variable">$INBOX_ID/messages/<span class="hljs-variable">$MSG_ID/body.html

<span class="hljs-comment"># Get spam report
curl -H <span class="hljs-string">"Api-Token: $TOKEN" https://mailtrap.io/api/inboxes/<span class="hljs-variable">$INBOX_ID/messages/<span class="hljs-variable">$MSG_ID/spam_report

What Mailtrap does well:

• Cloud-hosted, no local infrastructure
• Spam score analysis (SpamAssassin integration)
• HTML rendering across email clients (simulated Outlook, Gmail, Apple Mail)
• Team inboxes with access controls
• Email Sending product (production delivery, not just testing)
• Retention and history across test runs
• Official client libraries for Node.js, Python, Ruby, PHP

What Mailtrap lacks:

• Free tier is limited (100 emails/month on free, then paid)
• Requires network access (doesn't work offline or in air-gapped CI)
• SMTP credentials are per-project secrets to manage
• Latency for message delivery vs. localhost tools

Best for: Teams that want spam analysis, cross-client rendering checks, or shared inboxes accessible from anywhere.

Feature Comparison

CI Integration

Mailpit in GitHub Actions

services:
  mailpit:
    image: axllent/mailpit
    ports:
      - 1025:1025
      - 8025:8025

// jest.config.js — global setup
module.exports = {
  globalSetup: './test/setup/wait-for-mailpit.js',
};

// test/setup/wait-for-mailpit.js
const axios = require('axios');

module.exports = async () => {
  let retries = 20;
  while (retries--) {
    try {
      await axios.get('http://localhost:8025/api/v1/messages');
      return;
    } catch {
      await new Promise(r => setTimeout(r, 500));
    }
  }
  throw new Error('Mailpit did not start');
};

Mailtrap in GitHub Actions

env:
  MAILTRAP_USER: ${{ secrets.MAILTRAP_USER }}
  MAILTRAP_PASS: ${{ secrets.MAILTRAP_PASS }}
  MAILTRAP_API_TOKEN: ${{ secrets.MAILTRAP_API_TOKEN }}
  MAILTRAP_INBOX_ID: ${{ secrets.MAILTRAP_INBOX_ID }}

No service container needed—Mailtrap runs on their servers.

Which Tool Should You Use?

Use MailHog if: You're maintaining a legacy project that already uses it and don't want to change anything.

Use Mailpit if: You need a self-hosted solution, you're on an M1/M2 Mac, you want active maintenance, or you're replacing MailHog. It's the best local option in 2026.

Use Mailtrap if: You need spam analysis, cross-client rendering previews, shared team inboxes, or if you also plan to use their email sending product for production delivery.

Use both: Some teams run Mailpit locally (fast, offline) and Mailtrap in staging/pre-production CI where spam analysis matters.

Full-Stack Testing Beyond Email

Email testing catches delivery and content bugs, but production issues often span the whole user journey: form submission, trigger email, receive email, click link, complete action. For end-to-end testing of these workflows, HelpMeTest lets you write tests in plain English that automate the full signup and email verification flow without writing code.

Summary

• MailHog: archived, no ARM support, avoid for new projects
• Mailpit: modern MailHog replacement, ARM64 native, full API, best for local and CI
• Mailtrap: cloud SaaS, adds spam analysis and cross-client rendering, best when those features matter
• All three work as SMTP sinks configurable via standard Nodemailer/SMTP settings
• Mailpit is the default recommendation for most teams in 2026