Setting Up Mailcatcher

Oct 21, 2014


Handling email in applications can be hard.

Ensuring sent emails are designed, parsed and formatted correctly is a painstaking problem.

Mailcatcher is a program you can use to test sending email. It gives you the ability to inspect sent emails and their headers.

It is a simple SMTP server that can receive emails. It also gives you a nice web interface for inspecting sent emails.

We'll cover installing the dependencies for Mailcatcher. Then we'll install and set it up for easy use in our development environment. This includes use with PHP.


The first thing we need to do is install some dependencies. As usual, I'll assume we're using Ubuntu 14.04. This process will work for Debian and likely older Ubuntu versions.

We'll install some Mailcatcher dependencies as well as PHP. Then we can install Mailcatcher.

# Update repositories
sudo apt-get update

# Install Basics
# build-essential needed for "make" command
sudo apt-get install -y build-essential software-properties-common \
                        vim curl wget tmux

# Install PHP 5.6
sudo add-apt-repository -y ppa:ondrej/php5-5.6
sudo apt-get update
sudo apt-get install -y php5 php5-fpm php5-mcrypt php5-curl

# Install Mailcatcher Dependencies (sqlite, ruby)
sudo apt-get install -y libsqlite3-dev ruby1.9.1-dev

That does it for installing PHP and our dependencies. Next, we can install the Mailcatcher gem.

# Install Mailcatcher as a Ruby gem
sudo gem install mailcatcher

Once that's installed, we can see the available options:

$ mailcatcher --help
Usage: mailcatcher [options]
        --ip IP                      Set the ip address of both servers
        --smtp-ip IP                 Set the ip address of the smtp server
        --smtp-port PORT             Set the port of the smtp server
        --http-ip IP                 Set the ip address of the http server
        --http-port PORT             Set the port address of the http server
    -f, --foreground                 Run in the foreground
    -v, --verbose                    Be more verbose
    -h, --help                       Display this help information

Then we can can start using Mailcatcher. We'll bind the web interface's IP address to all networks:

mailcatcher --foreground --http-ip=

This will run Mailcatcher in the foreground. You can exit it by hitting Ctrl+C.

Local scripts can then connect to SMTP at localhost port 1025. Additionally, the web interface is available at port 1080 by default.

Start on Boot

It is useful to setup Mailcatcher to start when the server boots. This lets us forget about having to turn on Mailcatcher whenever we start our development machine.

Rather than install a process monitor, we can use Upstart, which currently comes out of the box with Ubuntu. This will get replaced with Systemd eventually. For now, we can use Upstart.

Create and edit file /etc/init/mailcatcher.conf:

description "Mailcatcher"

start on runlevel [2345]
stop on runlevel [!2345]


exec /usr/bin/env $(which mailcatcher) --foreground --http-ip=

Let's cover what this Upstart configuration is doing.

This configuration file tells Upstart to start Mailcatcher at runlevel 2,3,4 and 5. We can see what various runlevel's do here.

To explain the runlevels we'll use:

  • 2 - Start when the GUI is ready (not applicable on a headless server), and with networking. We care more about the network being ready.
  • 3-5 - These are unused in Ubuntu. They are the same as runlevel 2. These are useful to define if this configuration is used with other distributions.

Our configuration says to start when the above runlevels are reached and stop when the runlevels are absent.

The respawn directive tells Upstart to restart Mailcatcher if it fails.

Finally we set the command to start Mailcatcher. I used /usr/bin/env to find the environment's location of mailcatcher. This is useful as the location may change if Mailcatcher was installed using RVM or another environment manager for Ruby.

We configure Mailcatcher to run in the foreground with the --foreground option. Mailcatcher daemonizes by default. However, Upstart either needs to be told to expect daemon or to run the process in the foreground. The latter is simpler.

Once that file is created, you'll have a new service to control. You should be able to use to the following commands:

sudo service mailcatcher status
sudo service mailcatcher start
sudo service mailcatcher restart
sudo service mailcatcher stop

Run sudo service mailcatcher start to kick it off. Then you can head to the server's IP address at port 1080 to see the web interface!

mailcatcher web interface

Send Email in PHP

Let's setup PHP to be able to send email via the mail() function.

PHP needs the php.ini configuration sendmail_path set to the path of sendmail. Mailcatcher comes with the catchmail command, which can be used for this purpose.

We'll add a new configuration in PHP's mods-available directory. Then we'll enable that configuration for each of PHP's SAPIs.

Each SAPI is just the context in which PHP is run. For example, on the command line, within PHP-FPM, or loaded in Apache.

Here's the process for configuring PHP:

# Add config to mods-available for PHP
# -f flag sets "from" header for us
echo "sendmail_path = /usr/bin/env $(which catchmail) -f" | sudo tee /etc/php5/mods-available/mailcatcher.ini

# Enable sendmail config for all php SAPIs (apache2, fpm, cli)
sudo php5enmod mailcatcher

# Restart Apache if using mod_php
sudo service apache2 restart

# Restart PHP-FPM if using FPM
sudo service php5-fpm restart

Note that we set the -f flag for catchmail. This tells Mailcatcher to set the "from" header to when email is sent.

We can then send email in PHP:

if( mail('', 'Feedback', 'This is so useful, thanks!') )
    echo "Mail Sent!";

That's it! Mailcatcher is now setup for development use.

More Information

If you have questions on any of this, check out the Servers for Hackers book!

The Servers for Hackers book covers configuring Upstart, Supervisord, Circus and other process monitors.

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