# mailhog/MailHog

Web and API based SMTP testing

Repository: https://github.com/mailhog/MailHog
Canonical: https://ross.abutalabs.com/products/mailhog
Language: Go
License: MIT
License Family: permissive
Last push: 2024-02-13T18:38:41+00:00

## Health v2 (maintenance only)
Score: 23/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 0, release rhythm 8, longevity 100
- inputs: {"age_days": 4522, "days_push": 932, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 16138, forks 1180 (observed 2026-08-28T04:11:14.828857+00:00)

## What it is
MailHog is an email testing tool that runs a fake SMTP server and exposes a web UI and JSON API for inspecting outgoing messages. It can optionally release captured messages to real SMTP servers and supports in-memory, MongoDB, or file-based storage.

## Use cases
- test email sending in local development
- capture emails from my app without a real SMTP server
- inspect outgoing emails in a web UI
- retrieve test emails via a JSON API
- test SMTP failure scenarios with chaos monkey
- release captured test emails to a real mail server

## When to choose
- you need a lightweight, install-free fake SMTP server for development or CI
- you want a web UI plus API to inspect and manage test emails
- you need to simulate SMTP failures or auth during testing

## When to avoid
- you need a production mail transfer agent or actual email delivery
- you require actively developed features or frequent updates
- you need a hosted email testing service with team sharing

## Facets
- artifact type: application
- maturity: maintenance
- function: email, http-server, web-framework, testing
- domain: developer-tools, email, testing, self-hosted
- platform: windows, go, cross-platform
- tags: smtp-testing, fake-smtp, email-catcher, web-ui, -api, sendmail, linux, macos, docker

## Member repositories
- mailhog/MailHog (main) score 23

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:11:14.828857+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T17:05:13.477243+00:00, confidence not recorded.
  - readme: https://github.com/mailhog/MailHog (fetched 2026-08-28T04:11:14.828857+00:00, sha 35c7bc323773)
- Data as of 2026-08-30T08:39:29.467469+00:00.