Mailpit
Modern local SMTP catcher.
Mailpit is a single-binary local SMTP server and web UI for capturing email during development and testing. It listens on the same 1025 (SMTP) and 8025 (HTTP) ports as MailHog, so it drops into existing setups, and adds faster HTML rendering, full-text search, an HTML and link compatibility check, a spam-score view, and a REST API. It is actively maintained.
An agent stack treats email as a two-way primitive. Inbound has to arrive as structured JSON a tool call can consume, sends have to be safe to retry when a model loop repeats itself, and every action needs an audit trail. A provider without inbound parsing only solves half the problem.
Against inbound parsing into tool calls and model-generated sends that must not duplicate, Mailpit covers none of the capabilities this audience leans on (inbound parsing, idempotency keys, webhook coverage, event stream, batch sending, SDK breadth, and multi-tenant support), so it fits only where those needs are genuinely absent.
- Inbound parsing: No
- Idempotency keys: No
- Webhooks: No
- Operating since: Not published
- Event stream: No
- Best published rate per 1,000: Tiers not published in comparable form
- Batch sending: No
- SDKs: None
- Multi-tenant: No
Not applicable; capture-only.
Replacing MailHog in any local or CI email-capture setup.
Teams that need a shared cloud staging inbox rather than a local process per developer.
- › Single Go binary or small Docker image with no runtime dependencies
- › Reuses MailHog's 1025 and 8025 ports, so most existing configs work unchanged
- › Views for rendered HTML, plain text, raw source, headers, and attachments
- › Built-in HTML-compatibility check, link check, and spam-score view
- › REST API and real-time inbox updates for automated tests
- › Local development and staging only, not a production sender
- › No hosted or shared team-inbox mode
Features at a glance
| API | Yes |
| SMTP | Yes |
| SDKs | None |
| Webhooks | No |
| Templates | none |
| React Email | No |
| Batch send | No |
| Scheduled send | No |
| Suppressions | No |
| Multi-tenant | No |
| Inbound parsing | No |
| Event stream | No |
| Idempotency keys | No |
| Dedicated IP | No |