Frequently asked questions about MailSlurp.

What is MailSlurp?

MailSlurp is a modern email service for developers and QA teams.

What is MailSlurp used for?

MailSlurp can be used for anything email related: sending, receiving, and testing.

What can I do with MailSlurp?

MailSlurp has a lot of features. Here are some of them:

  • Create email addresses instantly
  • Send emails
  • Receive emails
  • Add custom domains
  • Use HTML templating
  • Send and receive attachments
  • Forward messages
  • Receive webhook notifications
  • Use web interface to manage emails
  • And more!

What can I test with MailSlurp?

MailSlurp is great for testing email related processes.

Think of every part of your app that relies on emails in some way:

  • User sign up
  • Password reset
  • Email notifications
  • Sharing links
  • Transactional emails and newsletters
  • Sending of attachments

You can test all these process and more with MailSlurp.


How do I sign up?

Sign up for free with the MailSlurp Dashboard.


What is an API Key?

An API Key is like a password for the MailSlurp API. It let’s you or your code communicate with MailSlurp and performs authenticated actions. We recommend treating your API Key like a password. Keep it safe and outside of version control.

How do I use my API Key?

You can find you API key once you sign up. It is displayed in the dashboard.


Send your API key as an x-api-key header with every HTTP request or configure the API client according to its documentation.


MailSlurp has a REST API available over HTTPS plus a range of SDK libraries in various langauges.

How do I call the MailSlurp API?

You can call the API using any programming language or use one of the prebuilt libraries in your language of choice.

Is there a graphical interface or app?

Yes! Check it out inside your dashboard.


What is MailSlurp built on?

MailSlurp runs on a several highly scalable Kubernetes clusters. Our APIs are backed by AWS cloud infrastructure and can handle large loads. Our infrastructure is battled tested and has very good up-time.


Many users use MailSlurp for testing email endpoints.

How is MailSlurp used in a test?

Most applications have tests. To test email functionality you include the MailSlurp SDK or call the REST API. A typical user sign-up test might do the following:

  • Create new email address with MailSlurp
  • Sign up as a new user with that email address
  • Use MailSlurp to receive and validate a welcome email that you expect your app to send

What languages does MailSlurp support?

Any programming langauge capable of making HTTP requests. You can find the API docs here. MailSlurp also provides official NodeJS packages plus a range of SDKs in other languages.


Does MailSlurp use SMTP?

Yes, under the hood MailSlurp uses real SMTP mail servers. We abstract that away for you and provide modern APIs for sending and receiving emails.

What email domain are emails sent with?

All free MailSlurp email addresses are under the mailslurp.com domain. Each time you create a new inbox a random UIID is generated and associated with the inbox. When emails are sent to <that-uuid>@mailslurp.com they are stored under the inbox associated with it.

Paid accounts can gain access to custom domains.

How do I receive emails with MailSlurp?

MailSlurp lets you create real, private test email accounts. First create an inbox via the API then send an email to it. Lastly use the API to list the emails in that inbox then fetch the one you want to read. For more information see the documentation.

How do I download attachments?

Attachments are available via the attachments endpoints. First fetch an email then use the attachment IDs listed in the response.

Can I use other domains?

MailSlurp paid plans offer custom domain integrations. Please contact support for more information.

How does MailSlurp store emails?

Emails are stored on encrypted disks accessible only to you. Storage is permanent until you delete the email or your account.


Is MailSlurp free?

MailSlurp is free for personal use! For more options see the pricing page.

What advantages do paid plans have?

Paid plans enable unlimited email addresses plus more sending and receiving per month. Enterprise plans enable many additional features.


Where are MailSlurp servers based?

MailSlurp has severs in Germany and the USA. You can request deployment in a specific region by contacting us.

Does MailSlurp read my messages?

No human ever accesses MailSlurp emails. Server code does however but only to extract data into API responses. No data is ever shared with any party ever.

Where can I get help?

Try the support page first or chat with us directly.