Catches mail and serves it through a dream.
Ruby CoffeeScript
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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:// instead of your default SMTP server, then check out to see the mail that's arrived so far.

MailCatcher screenshot


  • 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 open links in a new window. (currently very basic)
  • Can send HTML for analysis by Fractal.
  • 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.
  • Growl notifications when you receive a new message.
  • Runs as a daemon run in the background.
  • Sendmail-analogue command, catchmail, makes using mailcatcher from PHP a lot easier.
  • Written super-simply in EventMachine, easy to dig in and change.


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

The brave can get the source from the GitHub repository.


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

rvm default@mailcatcher --create gem install mailcatcher
rvm wrapper default@mailcatcher --no-prefix mailcatcher catchmail


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

config.action_mailer.delivery_method = :smtp
config.action_mailer.smtp_settings = { :host => "localhost", :port => 1025 }


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

You can do this in an Apache htaccess file or general configuration like so:

php_value sendmail_path "/usr/bin/env catchmail"

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.


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.


  • 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.
  • The interface is very basic and has not been tested on many browsers yet.


  • Add mail delivery on request, optionally multiple times.
  • Better Growl support in MacRuby and RubyCocoa with click notifications which takes you to the received message.
  • An API-compatible nodejs version, for fun and profit (and non-ruby npm users).
  • Test suite.
  • Compatibility testing against CampaignMonitor's design guidelines and CSS support matrix.
  • Forward mail to rendering service, maybe CampaignMonitor?
  • Package as an app? Native interfaces? HotCocoa?


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.

Thanks also to The Frontier Group for giving me the idea, being great guinea pigs and letting me steal pieces of time to keep the project alive.


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.


Copyright © 2010-2011 Samuel Cochran ( Released under the MIT License, see LICENSE for details.


For dream catching, try this. OR THIS, OMG.