Cuttlefish
Open-source transactional email server with a web UI.
Cuttlefish is a self-hosted transactional email server with SMTP delivery, bounce handling, open and click tracking, real-time analytics, a web UI, and an API. It runs on top of Postfix and is explicitly positioned as free and open source software.
Judged purely as an API. What the request contract guarantees on retry, how complete the webhook event coverage is, whether suppressions are readable and writable programmatically, and how much the message log retains when something needs debugging in production.
Against high-frequency programmatic sends where a missed delivery is a product failure, Cuttlefish covers event stream and the suppressions API, and does not cover idempotency keys, webhook coverage, batch sending, and SDK breadth. Whether that gap matters depends on how central those are to the build.
- Idempotency keys: No
- Webhooks: No
- Event stream: Yes
- Operating since: Not published
- Suppressions API: Yes
- Best published rate per 1,000: Tiers not published in comparable form
- Batch sending: No
- SDKs: None
- Deliverability: Self-hosted deliverability depends on Postfix configuration, IP reputation, DNS authentication, bounce processing, and list hygiene. Cuttlefish adds bounce suppression and analytics around SMTP delivery.
Self-hosted deliverability depends on Postfix configuration, IP reputation, DNS authentication, bounce processing, and list hygiene. Cuttlefish adds bounce suppression and analytics around SMTP delivery.
Teams that want a self-hosted transactional email dashboard in front of Postfix.
Teams that need managed deliverability, inbound parsing, or template tooling.
- › Open-source transactional email with a useful web UI
- › SMTP integration works with any framework or language
- › Bounce handling, open tracking, click tracking, and application-level analytics are built in
- › Project site describes the product as beta
- › Official site says it does not handle incoming email or built-in templates
- › Requires Postfix and self-hosted operations expertise
Features at a glance
| API | Yes |
| SMTP | Yes |
| SDKs | None |
| Webhooks | No |
| Templates | none |
| React Email | No |
| Batch send | No |
| Scheduled send | No |
| Suppressions | Yes |
| Multi-tenant | Yes |
| Inbound parsing | No |
| Event stream | Yes |
| Idempotency keys | No |
| Dedicated IP | No |