Mailpit vs SMTP Labs
Mailpit
mailpit.axllent.orgSMTP Labs
smtp.devSide by side
| Figure | Mailpit | SMTP Labs |
|---|---|---|
| Price from | Free | $7/mo |
| Free plan | Yes | Yes |
| Free trial | — | — |
| Open source | — | — |
| Web | Yes | Yes |
| Windows | Yes | — |
| macOS | Yes | — |
| Linux | Yes | — |
| API | Yes | Yes |
| Self-hosted | Yes | — |
| Plans published | 1 | 3 |
| Spec score · Email Testing Software | 8.6 (#6) | 8.4 (#8) |
| Integrations | The project says Mailpit is used by projects including Laravel, DDEV, Quarkus, and Saleor, and in CI/CD pipelines. | The maker documents CI use with GitHub Actions, Jenkins, GitLab CI, and CircleCI, using standard SMTP and the REST API. |
| Message inspection | The web UI can display formatted HTML, highlighted HTML source, text, headers, raw source, and MIME attachments with image thumbnails. | Messages can be viewed as HTML or plain text and examined as MIME structures, headers, attachments, or complete RFC 5322 source. |
| Purpose | Mailpit is an open-source utility for testing emails and SMTP delivery, with a local SMTP server, web interface, and integration-testing API. | SMTP Labs is an email testing service that receives test email over SMTP and lets users inspect it through the web UI, IMAP, POP3, or API. |
| Security controls | The web UI and API can use HTTPS and basic authentication, while SMTP supports optional STARTTLS or SSL/TLS and authentication. | The privacy policy says the service uses encryption, firewalls, SSL technology, and third-party authentication protections. |
| Support | The troubleshooting guide invites users to raise an issue after checking existing issues first. | The terms state the company has no support or maintenance obligation except as may be included in a paid subscription plan. |
Plans
In their own words
Mailpit
Mailpit is a free, open-source tool for checking email content and SMTP delivery without sending messages to real addresses. It runs a local SMTP server alongside a web interface and REST API, and is available for Linux, macOS, Windows, Docker, and self-hosted deployment. The interface displays formatted HTML, source, text, headers, raw messages, and MIME attachments with image thumbnails. Checks include HTML and link testing, message screenshots, and optional SpamAssassin scoring. The API can access, search, send, delete, tag, and release messages; messages can also be relayed, forwarded, or used to trigger configurable SMTP errors. Mailpit can send message-summary webhooks and offers a Cypress package for integration tests. The web UI and API can use HTTPS and basic authentication; SMTP supports optional authentication and TLS. By default, SMTP listens on port 1025 without encryption or authentication. Mailpit keeps the most recent 500 messages by default.
SMTP Labs
SMTP Labs is an email testing service that receives test messages over SMTP and lets you inspect them on the web, through IMAP or POP3, or via an API. Messages remain in a sandbox and cannot reach external recipients. Inspection includes HTML and plain text, headers, MIME structure, raw source, and attachments. SPF, DKIM, and DMARC checks appear in the interface and API, while a deliverability audit reviews sender configuration, HTML, links, and content patterns associated with spam filters. The REST API covers domains, accounts, mailboxes, messages, and tokens; server-sent events can push new messages. SMTP, IMAP, and POP3 work without a vendor SDK. The Lite plan is free at free with one domain, 50 accounts, and seven-day retention. Pro costs $7 a month, and Max costs $20 a month, with longer retention and expanded domains or accounts. Email and account data are primarily processed in the United States.