MailHog

Web · Mac · Linux · Self-hosted · API

Freedom report

Three barsScore 6.5

Free tierA free tier is on its own pricing page
Open codeNo open-source code on record
Runs widely3 of 6 device platforms
DocumentedPlans, terms and facts published

MailHog is ranked #3 of 28 in email testing software on Freedom251. It runs on API, Linux, macOS, Self-hosted, Web. There is a free plan.

MailHog plans and pricing

All plans

MailHog Free Open-source email testing tool · MIT license github.com · 4 Oct 2026

Compared on email testing software

Free plan: Yes
API access: Yes

Best MailHog alternatives

See all 12

Two bars Mailpit Free tier No. 1Free6.7 Two bars Twilio Segment Free tier No. 2$120/mo6.6 One bar Emailens Free tier No. 4$9/mo6.4 One bar GlockApps Free tier No. 5$59/mo6.4 One bar MailSlurp Free tier No. 6$19.99/mo6.4 One bar Mailtrap Email Sandbox Free tier No. 7$17/mo6.4

The record

Purpose: MailHog is an email testing tool for developers that accepts application mail over SMTP and lets users view messages in a web UI or retrieve them through a JSON API.
Message release: Messages can optionally be released to real SMTP servers for delivery.
SMTP: MailHog implements ESMTP RFC5321 and supports SMTP AUTH RFC4954 and PIPELINING RFC2920.
Web interface: The web interface displays messages as plain text, HTML, or source and supports RFC2047 encoded headers and real-time updates using EventSource.
HTTP API: The HTTP API can list, retrieve, and delete messages, and supports downloading complete messages and individual MIME parts.
Failure testing: MailHog includes a Chaos Monkey feature for failure testing.
Storage: Message storage can use memory, MongoDB, or Maildir; the default is in-memory storage.
Authentication: HTTP basic authentication can protect all HTTP requests, including static content and API endpoints, using a password file with bcrypt-hashed passwords.
Integrations: The project lists Node.js API v2 and PHP API v1/v2 client libraries and provides mhsendmail as a sendmail replacement.
Deployment: MailHog can be run from the command line, as a daemon, in Docker, or on AWS Elastic Beanstalk; the deployment guide also documents a SaltStack formula.
Default ports: By default, the SMTP server listens on port 1025 and the HTTP server listens on port 8025.
Notable limit: With in-memory storage, an Elastic Beanstalk deployment can use only a single MailHog instance; load-balanced deployments require MongoDB-backed storage.
Platform support: The README provides installation instructions for macOS, Debian/Ubuntu, FreeBSD, and Docker, and says MailHog runs without installation on multiple platforms.
License: MailHog is released under the MIT license.
Price from: Free

Where it ranks on Freedom251

Best Email Testing Software in 2026#3 of 28

Is MailHog yours?

Claim it for free: prove the domain, then correct facts, plans and screenshots. An editor reviews every change.

Claim it free Promote MailHog

Sources

github.com/mailhog/MailHog· checked 4 Oct 2026
github.com/mailhog/MailHog/blob/master/docs/CONFIG· checked 4 Oct 2026
github.com/mailhog/MailHog/blob/master/docs/Auth.m· checked 4 Oct 2026
github.com/mailhog/MailHog/blob/master/docs/DEPLOY· checked 4 Oct 2026