Inbox Monster vs Mailpit
Inbox Monster
inboxmonster.com
Mailpit
mailpit.axllent.orgSide by side
| Figure | Inbox Monster | Mailpit |
|---|---|---|
| Price from | $312.50/mo | Free |
| Free plan | — | Yes |
| Free trial | — | — |
| Open source | — | — |
| Web | Yes | Yes |
| Windows | — | Yes |
| macOS | — | Yes |
| Linux | — | Yes |
| API | — | Yes |
| Self-hosted | — | Yes |
| Plans published | 5 | 1 |
| Spec score · Email Testing Software | 7.6 (#20) | 8.6 (#6) |
| Integrations | Documented integrations include Salesforce Marketing Cloud, Braze, Iterable, SparkPost, Twilio SendGrid and Amazon SES. | The project says Mailpit is used by projects including Laravel, DDEV, Quarkus, and Saleor, and in CI/CD pipelines. |
| Purpose | Inbox Monster provides tooling for creative rendering, inbox intelligence and email deliverability for global email teams. | Mailpit is an open-source utility for testing emails and SMTP delivery, with a local SMTP server, web interface, and integration-testing API. |
| Security controls | The Trust Center lists audit logging, data security, multifactor authentication, penetration testing and encryption-at-rest documentation. | The web UI and API can use HTTPS and basic authentication, while SMTP supports optional STARTTLS or SSL/TLS and authentication. |
Plans
Inbox Monster
- Essential (Creative suite)$3,750 a year
- SMS suite$6,000 a year
- Advanced (Creative suite)$6,500 a year
- Enterprise (Creative suite)$10,000 a year
- Deliverability suite$15,000 a year
In their own words
Inbox Monster
Inbox Monster has no write-up on Specifiction yet; its figures are above.
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.