Mailpit Review (2026): Pricing, Features & Honest Verdict

TLDR

Mailpit is a free, open-source email testing tool that catches SMTP messages locally and displays them in a clean web UI. Best for: developers who need a lightweight, self-hosted email catcher for local development. Price: Free (open source). Rating: 8.3/10

What is Mailpit?

Mailpit is a local email testing tool built in Go that acts as an SMTP server, catching all outgoing emails from your development environment and displaying them in a web interface. Think of it as a mailbox that sits between your app and the real world, letting you inspect every email without anything actually getting delivered. It was created as a modern replacement for MailHog, which has been largely unmaintained since 2020.

Written by Ralph Slooten (axllent.org), Mailpit ships as a single binary with zero dependencies. You download it, run it, and it starts catching emails. No Docker required (though Docker images are available), no database setup, no configuration files. It just works. The project has gained significant traction in the developer community, with active development and regular releases.

Key Features

SMTP Catching

Mailpit runs a local SMTP server (default port 1025) that accepts all incoming emails regardless of recipient. Point your application SMTP settings at localhost:1025 and every email your app generates gets caught and stored. This covers everything from user registration emails to password resets to order confirmations. No email ever leaves your machine, which eliminates the risk of test data hitting real inboxes.

Web UI

The built-in web interface (default port 8025) displays all caught emails in a familiar inbox-style layout. You can view HTML and plain text versions, inspect headers, download attachments, and check raw source. The UI is responsive and works well on mobile, which is handy for checking emails on the go during development. Search across all messages works instantly, even with thousands of stored emails.

REST API

Mailpit exposes a REST API that lets you query, search, and manage captured emails programmatically. This is essential for integration testing, where your test suite needs to verify that certain emails were sent with the right content. The API supports filtering by sender, recipient, subject, and body content, making it easy to write assertions in your test framework of choice.

Message Search and Filtering

The search functionality covers all message fields including headers, body text, and attachment names. You can filter by read/unread status, date range, and specific recipients. For teams working on apps that generate dozens of different email types, this keeps things manageable. Saved searches would be a nice addition, but the real-time filtering is fast enough that it rarely matters.

HTML and Text Preview

Each captured email can be viewed in HTML rendered mode, plain text mode, or raw source. The HTML preview accurately reflects how the email would look in a real client, while the source view lets you debug template rendering issues. You can also check the email headers for MIME type handling, encoding, and other technical details that affect deliverability.

Lightweight and Fast

Being written in Go, Mailpit compiles to a single binary that uses minimal resources. It starts in under a second and handles thousands of emails without breaking a sweat. The embedded storage (using BadgerDB) requires no external database. Compare this to MailHog, which could become sluggish with large message volumes and had known memory leak issues.

Pricing

Mailpit is completely free and open source under the MIT license. There are no paid tiers, no premium features locked behind a paywall, and no usage limits. You can run it locally, on a shared dev server, or in CI/CD pipelines without any cost. The entire feature set is available to everyone.

Pros and Cons

Pros

• Completely free and open source with no feature restrictions
• Single binary with zero dependencies, runs anywhere
• Clean, responsive web UI that works on mobile
• REST API enables automated email testing in CI/CD
• Actively maintained, unlike the stagnating MailHog
• Extremely lightweight on system resources

Cons

• No cloud-hosted option, you must run it yourself
• No email rendering previews across different clients (Outlook, Gmail, etc.)
• No built-in spam score checking or deliverability analysis
• Limited documentation compared to commercial alternatives

Who Should Use Mailpit?

Mailpit is ideal for any developer or team that needs local email testing during development. If you are building a web app that sends transactional emails, Mailpit catches them so you can verify content, layout, and headers without configuring a real SMTP service. It slots naturally into Docker Compose setups for local development environments.

Freelancers and solo developers benefit the most since the tool is free and requires almost no setup. Larger teams can run it on a shared development server so everyone can inspect test emails. For CI/CD pipelines, the API makes it straightforward to assert email behavior in automated tests.

Where Mailpit falls short is production-level email concerns. It does not test deliverability, check spam scores, or preview rendering across email clients. If you need those capabilities, a commercial tool like Mailtrap fills that gap. Mailpit is strictly for catching and inspecting emails during development, and it does that job exceptionally well.

Alternatives

Mailtrap

A commercial email testing platform with sandbox catching, deliverability checking, HTML previews across email clients, and production sending. Mailtrap offers more features but starts at $10/mo for sending and $15/mo for testing beyond the free tier. Choose Mailtrap when you need cross-client rendering previews and deliverability analysis alongside basic email catching.

MailHog

The predecessor that Mailpit was built to replace. MailHog served the developer community well for years but has not seen meaningful updates since 2020. It has known memory leak issues with large message volumes and a less polished UI. If you are currently using MailHog, switching to Mailpit is a straightforward upgrade with better performance and active maintenance.

Papercut

A Windows-focused local SMTP testing tool with a desktop application UI. Papercut is simple and effective on Windows but lacks the cross-platform support and API that Mailpit offers. If your development environment is Windows-only and you prefer a native desktop app over a web interface, Papercut is worth a look.

FAQ

How do I install Mailpit?

Download the binary for your OS from the GitHub releases page, or use Docker (docker run -p 8025:8025 -p 1025:1025 axllent/mailpit). On macOS you can also install via Homebrew: brew install mailpit. No additional configuration is needed to get started.

Can Mailpit replace MailHog?

Yes. Mailpit was specifically designed as a MailHog replacement. It uses the same default ports (SMTP 1025, Web UI 8025), so in most cases you can swap it in by just changing the binary. The API is different, so any code using the MailHog API will need updates.

Does Mailpit work in Docker Compose?

Yes. Add the official Docker image to your docker-compose.yml and point your app SMTP settings to the Mailpit service on port 1025. The web UI will be available on port 8025. This is the most common setup for teams using containerized development environments.