mailcatcher

Catches mail and serves it through a dream.

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mailpit

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maildev

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:mailbox: SMTP Server + Web Interface for viewing and testing emails during development.

inbucket

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Disposable webmail server (similar to Mailinator) with built in SMTP, POP3, RESTful servers; no DB required.

Quick Overview

MailCatcher is a simple SMTP server that catches all outgoing emails and displays them in a web interface for easy testing and debugging of email functionality in applications. It's particularly useful for development environments where you want to inspect emails without actually sending them to real recipients.

Pros

Easy to set up and use, with minimal configuration required
Provides a clean web interface to view caught emails, including HTML and plain text versions
Supports multiple applications sending emails simultaneously
Can be integrated into various development workflows and testing environments

Cons

Not suitable for production use, as it's designed for development and testing only
May require additional setup when used with certain frameworks or in complex environments
Limited search and filtering capabilities in the web interface
No built-in email forwarding or resending functionality

Getting Started

To install and run MailCatcher:

# Install MailCatcher
gem install mailcatcher

# Start MailCatcher
mailcatcher

# Configure your application to use MailCatcher's SMTP server
# Usually, this means setting the SMTP server to localhost:1025

# Access the web interface at http://localhost:1080

To use MailCatcher with Rails, add the following to your config/environments/development.rb:

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

For other frameworks or languages, configure your SMTP settings to use localhost as the server and port 1025.

Competitor Comparisons

mailpit

7,456

An email and SMTP testing tool with API for developers

Pros of Mailpit

Written in Go, offering better performance and lower resource usage
Supports SMTP AUTH for secure email testing
Provides a modern, responsive web UI with real-time updates

Cons of Mailpit

Relatively newer project with potentially fewer community contributions
May lack some advanced features found in more established tools

Code Comparison

Mailpit (Go):

func main() {
    server := smtp.NewServer()
    server.Addr = ":1025"
    server.Handler = mailpit.New()
    log.Fatal(server.ListenAndServe())
}

Mailcatcher (Ruby):

require 'mailcatcher'

MailCatcher.run! do
  serve_messages
  serve_web
end

Key Differences

Language: Mailpit is written in Go, while Mailcatcher is in Ruby
Performance: Mailpit likely offers better performance due to Go's efficiency
Features: Mailpit includes SMTP AUTH, while Mailcatcher focuses on simplicity
UI: Mailpit provides a more modern, responsive interface
Community: Mailcatcher has a larger user base and longer history

Conclusion

Both Mailpit and Mailcatcher serve as useful tools for catching and inspecting emails during development. Mailpit offers potential performance advantages and some additional features, while Mailcatcher benefits from a more established ecosystem. The choice between them may depend on specific project requirements and personal preferences.

MailHog

15,110

Web and API based SMTP testing

Pros of MailHog

Written in Go, making it more performant and easier to deploy across platforms
Supports SMTP AUTH (PLAIN/CRAM-MD5/LOGIN)
Provides a more modern and feature-rich web UI

Cons of MailHog

Larger binary size due to being written in Go
May require more system resources compared to MailCatcher

Code Comparison

MailHog (Go):

func CreateMail(from string, to []string, subject string, body string) []byte {
    header := make(textproto.MIMEHeader)
    header.Set("From", from)
    header.Set("To", strings.Join(to, ", "))
    header.Set("Subject", subject)
    header.Set("Content-Type", "text/plain; charset=UTF-8")
    return []byte(header.String() + "\r\n" + body)
}

MailCatcher (Ruby):

def build_mail(from, to, subject, body)
  mail = Mail.new do
    from    from
    to      to
    subject subject
    body    body
  end
  mail.to_s
end

Both projects serve as SMTP servers for testing email in development environments. MailHog offers more features and better performance, while MailCatcher is lighter and simpler to set up. The choice between them depends on specific project requirements and preferences.

smtp4dev

3,540

smtp4dev - the fake smtp email server for development and testing

Pros of smtp4dev

Built with modern technologies (.NET Core, React)
Supports IMAP protocol in addition to SMTP
More actively maintained with frequent updates

Cons of smtp4dev

Requires .NET runtime, which may not be available on all systems
More complex setup compared to MailCatcher's Ruby-based installation
Larger resource footprint due to its feature-rich nature

Code Comparison

MailCatcher (Ruby):

require 'mail_catcher'

MailCatcher.run!

smtp4dev (.NET):

using Rnwood.Smtp4dev;

var server = new Smtp4devServer();
server.Start();

Feature Comparison

MailCatcher:

Simple Ruby-based implementation
Web interface for viewing caught emails
Easy to set up and use in Ruby environments

smtp4dev:

More comprehensive email testing solution
Supports both SMTP and IMAP protocols
Offers advanced features like message relaying and SSL/TLS support

Community and Maintenance

MailCatcher:

Large user base in the Ruby community
Less frequent updates in recent years

smtp4dev:

Growing popularity across different development ecosystems
Regular updates and active issue resolution

Both tools serve the purpose of catching and displaying emails during development, but smtp4dev offers a more feature-rich experience at the cost of increased complexity and system requirements.

maildev

5,593

:mailbox: SMTP Server + Web Interface for viewing and testing emails during development.

Pros of Maildev

Built with Node.js, making it easier to integrate with JavaScript-based projects
Offers a more modern and feature-rich web interface
Supports SMTP authentication and SSL/TLS

Cons of Maildev

May have a larger footprint due to Node.js dependencies
Potentially slower startup time compared to MailCatcher

Code Comparison

MailCatcher (Ruby):

require 'mail_catcher'

MailCatcher.run!

Maildev (JavaScript):

const MailDev = require('maildev');

const maildev = new MailDev();
maildev.listen();

Both MailCatcher and Maildev are tools for testing email in development environments. MailCatcher is written in Ruby and provides a simple SMTP server and web interface. Maildev, on the other hand, is built with Node.js and offers a more modern approach with additional features.

Maildev's Node.js foundation makes it a natural fit for JavaScript-heavy projects, while MailCatcher may be more suitable for Ruby-based applications. Maildev's web interface is generally considered more user-friendly and feature-rich, offering better email rendering and management capabilities.

However, Maildev's reliance on Node.js may result in a larger installation footprint and potentially slower startup times compared to the lightweight MailCatcher. The choice between the two often depends on the specific project requirements and the development team's preferences.

inbucket

1,868

Disposable webmail server (similar to Mailinator) with built in SMTP, POP3, RESTful servers; no DB required.

Pros of Inbucket

More actively maintained with recent updates
Supports multiple storage backends (memory, file system, MongoDB)
Offers a REST API for programmatic access to messages

Cons of Inbucket

Lacks a built-in SMTP server, requiring external configuration
More complex setup compared to MailCatcher's simplicity
Does not provide a web interface for viewing HTML emails

Code Comparison

MailCatcher (Ruby):

require 'mail'
require 'eventmachine'

EM.run do
  EM::start_server '0.0.0.0', 1025, SMTPServer
end

Inbucket (Go):

package main

import (
    "github.com/inbucket/inbucket/pkg/server"
    "github.com/inbucket/inbucket/pkg/storage"
)

func main() {
    server.Start(storage.NewMemoryStore())
}

Both projects aim to simplify email testing in development environments. MailCatcher is written in Ruby and provides a straightforward solution with an integrated SMTP server and web interface. Inbucket, written in Go, offers more flexibility in terms of storage options and API access but requires additional configuration for SMTP functionality.

MailCatcher's simplicity makes it easier to set up and use out of the box, while Inbucket's modular approach and additional features cater to more complex testing scenarios and integration needs.

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README

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

gem install mailcatcher
mailcatcher
Go to http://127.0.0.1:1080/
Send mail through smtp://127.0.0.1:1025

Command Line Options

Use mailcatcher --help to see the command line options.

Usage: mailcatcher [options]

MailCatcher v0.8.0

        --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
        --messages-limit COUNT       Only keep up to COUNT most recent messages
        --http-path PATH             Add a prefix to all HTTP paths
        --no-quit                    Don't allow quitting the process
    -f, --foreground                 Run in the foreground
    -b, --browse                     Open web browser
    -v, --verbose                    Be more verbose
    -h, --help                       Display this help information
        --version                    Display the current version

Upgrading

Upgrading works the same as installation:

gem install mailcatcher

Ruby

If you have trouble with the setup commands, make sure you have Ruby installed:

ruby -v
gem environment

You might need to install build tools for some of the gem dependencies. On Debian or Ubuntu, apt install build-essential. On macOS, xcode-select --install.

If you encounter issues installing thin, try:

gem install thin -v 1.5.1 -- --with-cflags="-Wno-error=implicit-function-declaration"

Bundler

Please don't put mailcatcher into your Gemfile. It will conflict with your application's 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

Docker

There is a Docker image available on Docker Hub:

$ docker run -p 1080 -p 1025 sj26/mailcatcher
Unable to find image 'sj26/mailcatcher:latest' locally
latest: Pulling from sj26/mailcatcher
8c6d1654570f: Already exists
f5649d186f41: Already exists
b850834ea1df: Already exists
d6ac1a07fd46: Pull complete
b609298bc3c9: Pull complete
ab05825ece51: Pull complete
Digest: sha256:b17c45de08a0a82b012d90d4bd048620952c475f5655c61eef373318de6c0855
Status: Downloaded newer image for sj26/mailcatcher:latest
Starting MailCatcher v0.9.0
==> smtp://0.0.0.0:1025
==> http://0.0.0.0:1080

How those ports appear and can be accessed may vary based on your Docker configuration. For example, your may need to use http://127.0.0.1:1080 etc instead of the listed address. But MailCatcher will run and listen to those ports on all IPs it can from within the Docker container.

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/parts/: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.

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

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