Fake SMTP servers for safe testing that prevent any outbound emails from reaching real users

Test emails safely with no risk of spamming users with real emails

MailSlurp virtual inboxes are email addresses with fake SMTP servers that allow you to trap email sending during tests and avoid spamming real users. Virtual email accounts are perfect for application testing and transactional emails. They are a safe way to test without the risk of real users receiving spammy messages.

fake smtp server

How to create a fake SMTP mail server

You can create virtual inboxes easily with MailSlurp's email API clients. Here is an example using the Javascript email library:

const MailSlurp = require('mailslurp-client').default;
const mailslurp = new MailSlurp({
  apiKey: process.env.API_KEY ?? 'your-api-key',

// create a virtual inbox
const inbox = await mailslurp.inboxController.createInbox({
  virtualInbox: true,


Test emails safely with zero maintenance and a quick setup.

Separate inboxes for every environment

Create individual inboxes for each environment or review server for your application. Test email actions on each commit using real email accounts that can receive emails but will never send emails to any of your customers.

Connect to fake SMTP with any tool

MailSlurp SMTP inboxes can virtual meaning you can connect using any SMTP tool.

No real emails are sent

Virtual inboxes won't connect to any outside mail servers and capture all emails you send into a virtual sent box. Zero risk of accidentally emailing real users.

Capture emails easily with MailSlurp

How to get started in 3 easy steps:

Sign up for MailSlurp and get SMTP access

Create an account and open the configuration for SMTP and IMAP access credentials. You can alternatively use Postman or SDK libraries in over 10+ languages and frameworks.

Integrate your email client, application, or tests

Use the SMTP and IMAP settings to configure your tests or server so that emails sent during testing or in staging environments is caught by virtual inboxes.

Check the virtual sent email records or automate it

Every email you send using the fake SMTP servers will be caught. You can view the emails that would have been sent in the MailSlurp dashboard or using code.