A handy SMTP mail server useful for local and team application development.

What is MailSlurper?

MailSlurper is a small SMTP mail server that slurps mail into oblivion! MailSlurper is perfect for individual developers or small teams writing mail-enabled applications that wish to test email functionality without the risk or hassle of installing and configuring a full blown email server. It's simple to use! Simply setup MailSlurper, configure your code and/or application server to send mail through the address where MailSlurper is running, and start sending emails! MailSlurper will capture those emails into a database for you to view at your leisure.

Designed for developers

If you are an individual developer, or a member of a team, MailSlurper can help you. A simple, effective user-interface allows you to quickly find and inspect emails sent out of your applications.


Small and fast, MailSlurper easily runs on developer laptops, commodity hardware, or small virtual machines. It is designed to handle thousands of concurrent connections and work with various databases: SQLite, MSSQL, and MySQL.

Open Source

Open source product licensed under the permissive MIT license, it is both developer and enterprise friendly. No vendor lock-in, free to use and modify!



Default theme Default theme

Lumen Lumen theme

Readable Lumen theme

Slate Slate theme

SpaceLab SpaceLab theme

Get Started


To begin first you must download the version of MailSlurper for your operating system. If you are on a Mac running OSX you will need to download the file named If you are going to run MailSlurper on Windows download the file named


The next step is to extract the contents somewhere. It does not particularly matter where. Once extracted you will wish to review the configuration details in config.json. For this example let's say you are going to run MailSlurper on your local machine. There are three addresses and ports that need to be configured.

  1. Web application address and port
  2. Services address and port
  3. SMTP server address and port
Let's see what that might look like if we wanted to access the web-based administrator using http://localhost:8080, with services running on port 8888 and the SMTP server running on port 25.

	"wwwAddress": "",
	"wwwPort": 8080,
	"serviceAddress": "",
	"servicePort": 8888,
	"smtpAddress": "",
	"smtpPort": 25,
	"dbEngine": "SQLite",
	"dbHost": "",
	"dbPort": 0,
	"dbDatabase": "./mailslurper.db",
	"dbUserName": "",
	"dbPassword": "",
	"maxWorkers": 1000

Running MailSlurper

Now that you have MailSlurper configured all that is left to do is run it. Run the executable file named mailslurper for OSX, mailslurper.exe for Windows. Now open your favorite web browser and browse to http://localhost:8080. Congratulations! MailSlurper is now ready to slurp up mail for any of your applications and development projects setup to send mail to localhost on port 25!

Main interface screenshot Open attachment screenshot Search window screenshot Settings screenshot

Full Documentation

For more information on installing, configuring and using MailSlurper visit the Github wiki site.

MailSlurper Wiki


MailSlurper is developed and maintained by Adam Presley for developers and teams, and it is 100% free under the MIT License. This means the following.

  • You may use this product for personal and/or commercial use.
  • You may make modifications to the source code
  • You may distribute the source and/or compiled code
  • The work is provided "as is". You may not hold me the author liable
  • You must include copyright information in all copies and uses of this work
  • You must include the license notice in all copies or uses of this work

Have you found MailSlurper useful to you or your team? Consider buying me a beer or coffee with a PayPal donation!


I hope you find MailSlurper useful.
Feel free to get in touch if you have any questions or suggestions.

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Interested in more developer-centric stuff?

I tweet from time to time about software development at @adampresley. I also keep a blog where sometimes I talk about code I write, how it's done, and my learning experiences at

Adam Presley
Software Architect

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