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Mailsocket or Mailpit?
Both help you test email. They solve different problems, and many teams use both.
Checked October 2026. Prices and features change, so every Mailpit fact on this page links to Mailpit's own page as the source. Please check there before you decide.
The short answer
Mailpit is a great tool. It is free and open source (MIT licence), and it acts as an SMTP server with a web interface and a REST API, so you can catch and inspect the mail your own app sends in local and staging environments (source).
mailsocket is for a different job: real inboxes on the internet that receive mail from third parties. Think OAuth and identity providers, SaaS signups, or a CI run against real senders. Each test can create its own isolated inbox, the OTP or magic link is extracted for you, and there is no mail server to run.
Side by side
| Mailpit | mailsocket | |
|---|---|---|
| Price | ✅ Free, open source (MIT) (source) | Free plan (3 inboxes, 1,000 / month); paid plans from $12/mo |
| Who runs it | You do: a single binary or a Docker image (source) | ✅ Hosted, nothing to install or run |
| Works offline, on your laptop | ✅ Yes (source) | ❌ No, it needs internet access |
| Catches mail your app sends over SMTP | ✅ Yes, it is an SMTP server (source) | ❌ No, your app sends mail normally and it arrives like any other email |
| Receives mail from third parties on the internet | Not listed in its features (source) | ✅ Yes, real addresses on in.inboxpipe.net |
| OTP and magic link extracted to JSON | Not listed in its features (source) | ✅ Yes, every plan |
| One call that waits for the code | Not listed in its features (source) | ✅ Yes, up to 25s per call, every plan |
| HTML, link and spam checks | ✅ Yes (source) | ❌ No |
| Simulated SMTP errors (chaos testing) | ✅ Yes (source) | ❌ No |
| Webhook on new mail | ✅ Optional (source) | ✅ From the Pro plan |
| MCP server for AI agents | Not listed in its features (source) | ✅ Yes, every plan |
When Mailpit is the better choice
- You only need to see the mail your own app sends, in local development or a staging environment.
- You want something free and open source that you control, with no account and no outside service.
- You need to work offline, or mail must never leave your network.
- You want to check how an email renders, test its links, or score it for spam before it goes out.
In those cases Mailpit is the simpler and cheaper answer, and we would recommend it.
When to choose mailsocket
- The email comes from someone else: an OAuth or identity provider, a SaaS product you sign up to, or your production mail provider. A local SMTP catcher never sees that mail.
- You run tests in parallel and want each test to have its own inbox, created by one API call and isolated from the others.
- You want the code, not the email: one call waits until the OTP or magic link arrives and returns it as JSON.
- You do not want to run, secure or upgrade a mail server in CI.
- An AI agent needs an inbox: there is an MCP server, and an agent can get an API key without a signup form.
Try mailsocket
See it work without an account: the live demo creates an inbox and waits for a code in your browser. When you are ready, sign up for free to get an API key.
Spotted something out of date? Email support@mailsocket.app. See also: all comparisons.