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.
The question here is which one a backend engineer would rather operate. That means SDK depth in the language already in use, whether a retry can safely be replayed, how much the event log tells you when a customer says the email never arrived, and whether the pricing curve stays sane as volume grows.
Against password resets, receipts, and magic links shipped from application code, Cuttlefish covers developer experience and event stream, and does not cover SDK breadth, idempotency keys, and webhook coverage. Whether that gap matters depends on how central those are to the build.
- DX score: 6/10
- SDKs: None
- Idempotency keys: No
- Operating since: Not published
- Event stream: Yes
- Best published rate per 1,000: Tiers not published in comparable form
- Webhooks: No
- 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.
- Free tier: Free self-hosted, open source
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 |