# ryanb/letter_opener

Preview mail in the browser instead of sending.

Repository: https://github.com/ryanb/letter_opener
Canonical: https://ross.abutalabs.com/products/letter_opener
Language: Ruby
License: MIT
License Family: permissive
Last push: 2026-04-25T13:24:46+00:00

## Health v2 (maintenance only)
Score: 68/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 79, release rhythm 35, longevity 100
- inputs: {"age_days": 5474, "days_push": 130, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 3842, forks 244 (observed 2026-08-28T04:08:23.994496+00:00)

## What it is
A Ruby gem that intercepts outgoing email in development and previews it in the browser instead of sending it. It integrates with Rails ActionMailer, the Mail gem, and Pony as a custom delivery method.

## Use cases
- preview emails in browser during rails development
- avoid accidentally sending test emails to real users
- test actionmailer emails without an smtp server
- inspect email content and metadata locally
- set up mail delivery for a non-rails ruby app

## When to choose
- you develop Rails or Ruby apps and need safe local email previews
- you want zero-config email testing without external services
- you run your app locally and can open a browser

## When to avoid
- your app runs on a remote staging server or VM with no local browser
- you need to test actual SMTP delivery behavior
- you need shared team access to sent test emails

## Facets
- artifact type: library
- maturity: stable
- function: email, developer-tools, testing
- domain: web-development, developer-tools, email
- platform: ruby, cross-platform
- tags: rails, action-mailer, email-preview, development-environment, mail-gem

## Member repositories
- ryanb/letter_opener (main) score 68

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:08:23.994496+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 2026-08-29T18:26:13.399228+00:00, confidence not recorded.
  - readme: https://github.com/ryanb/letter_opener (fetched 2026-08-28T04:08:23.994496+00:00, sha 169c3f5a1823)
- Data as of 2026-08-30T08:39:29.467469+00:00.