mailcatcher

Ruby gem that deploys a simply SMTP MTA gateway that accepts all mail and displays in web interface. Useful for debugging or development.
11 Apr 2020500051

MailCatcher

Catches mail and serves it through a dream.

MailCatcher runs a super simple SMTP server which catches any message sent to it to display in a web interface. Run mailcatcher, set your favourite app to deliver to smtp://127.0.0.1:1025 instead of your default SMTP server, then check out http://127.0.0.1:1080 to see the mail that's arrived so far.

MailCatcher screenshot

Features

  • Catches all mail and stores it for display.
  • Shows HTML, Plain Text and Source version of messages, as applicable.
  • Rewrites HTML enabling display of embedded, inline images/etc and opens links in a new window.
  • Lists attachments and allows separate downloading of parts.
  • Download original email to view in your native mail client(s).
  • Command line options to override the default SMTP/HTTP IP and port settings.
  • Mail appears instantly if your browser supports WebSockets, otherwise updates every thirty seconds.
  • Runs as a daemon in the background, optionally in foreground.
  • Sendmail-analogue command, catchmail, makes using mailcatcher from PHP a lot easier.
  • Keyboard navigation between messages

How

  1. gem install mailcatcher
  2. mailcatcher
  3. Go to http://127.0.0.1:1080/
  4. Send mail through smtp://127.0.0.1:1025

Use mailcatcher --help to see the command line options. The brave can get the source from the GitHub repository.

Bundler

Please don't put mailcatcher into your Gemfile. It will conflict with your applications gems at some point.

Instead, pop a note in your README stating you use mailcatcher, and to run gem install mailcatcher then mailcatcher to get started.

RVM

Under RVM your mailcatcher command may only be available under the ruby you install mailcatcher into. To prevent this, and to prevent gem conflicts, install mailcatcher into a dedicated gemset with a wrapper script:

rvm default@mailcatcher --create do gem install mailcatcher
ln -s "$(rvm default@mailcatcher do rvm wrapper show mailcatcher)" "$rvm_bin_path/"

Rails

To set up your rails app, I recommend adding this to your environments/development.rb:

config.action_mailer.delivery_method = :smtp
config.action_mailer.smtp_settings = { :address => '127.0.0.1', :port => 1025 }
config.action_mailer.raise_delivery_errors = false

PHP

For projects using PHP, or PHP frameworks and application platforms like Drupal, you can set PHP's mail configuration in your php.ini to send via MailCatcher with:

sendmail_path = /usr/bin/env catchmail -f some@from.address

You can do this in your Apache configuration like so:

php_admin_value sendmail_path "/usr/bin/env catchmail -f some@from.address"

If you've installed via RVM this probably won't work unless you've manually added your RVM bin paths to your system environment's PATH. In that case, run which catchmail and put that path into the sendmail_path directive above instead of /usr/bin/env catchmail.

If starting mailcatcher on alternative SMTP IP and/or port with parameters like --smtp-ip 192.168.0.1 --smtp-port 10025, add the same parameters to your catchmail command:

sendmail_path = /usr/bin/env catchmail --smtp-ip 192.160.0.1 --smtp-port 10025 -f some@from.address

Django

For use in Django, add the following configuration to your projects' settings.py

if DEBUG:
    EMAIL_HOST = '127.0.0.1'
    EMAIL_HOST_USER = ''
    EMAIL_HOST_PASSWORD = ''
    EMAIL_PORT = 1025
    EMAIL_USE_TLS = False

API

A fairly RESTful URL schema means you can download a list of messages in JSON from /messages, each message's metadata with /messages/:id.json, and then the pertinent parts with /messages/:id.html and /messages/:id.plain for the default HTML and plain text version, /messages/:id/:cid for individual attachments by CID, or the whole message with /messages/:id.source.

Caveats

  • Mail processing is fairly basic but easily modified. If something doesn't work for you, fork and fix it or file an issue and let me know. Include the whole message you're having problems with.
  • Encodings are difficult. MailCatcher does not completely support utf-8 straight over the wire, you must use a mail library which encodes things properly based on SMTP server capabilities.

TODO

  • Add mail delivery on request, optionally multiple times.
  • Compatibility testing against CampaignMonitor's design guidelines and CSS support matrix.
  • Forward mail to rendering service, maybe CampaignMonitor?

Thanks

MailCatcher is just a mishmash of other people's hard work. Thank you so much to the people who have built the wonderful guts on which this project relies.

Donations

I work on MailCatcher mostly in my own spare time. If you've found Mailcatcher useful and would like to help feed me and fund continued development and new features, please donate via PayPal. If you'd like a specific feature added to MailCatcher and are willing to pay for it, please email me.

License

Copyright © 2010-2019 Samuel Cochran (sj26@sj26.com). Released under the MIT License, see LICENSE for details.