# Mailpit

SMTP you catch. Mailpit is MIT — Mailtrap without the hosted inbox seat.

**Replaces:** Mailtrap

**Tier:** Easy

## Problem

Mailtrap is a hosted fake SMTP inbox for staging mail. You wanted to catch messages on a box you run. Mailpit is MIT (axllent/mailpit; last push 22 Oct 2026) — an SMTP server plus a web UI and an API. This is not Mailtrap's every QA, email-API, or deliverability SKU. Production send stays on /replace/postmark (Plunk / Resend). A mailbox you live in stays on /replace/gmail. MailHog is unmaintained — not the published path.

## Stack

- [Mailpit](https://mailpit.axllent.org) — MIT SMTP catcher and web UI — the published Mailtrap path

## Estimated SaaS cost saved

| You stop paying | Typical / year | Self-host instead |
|---|---:|---|
| Mailtrap / hosted test inbox (small team) | $1,200 | Mailpit |

**About $1,200 / year** on a small team, before you count lock-in.

## Deploy on Railway

Placeholder: Mailpit (official image) plus a volume if you persist messages. Bind HTTP to 0.0.0.0:$PORT. SMTP on the documented port. No one-click template in this repo yet — Start on Railway. Production send stays on /stacks/plunk-newsletter.

[Start on Railway](https://c17.io/go/railway/mailpit-smtp?from=%2Fstacks%2Fmailpit-smtp.md)

[Plunk if this is production send, not a catch inbox](https://c17.io/stacks/plunk-newsletter)

## AGENT_PROMPT

```
Replace Mailtrap with Mailpit (https://mailpit.axllent.org).

- Official image. Point the app's SMTP at Mailpit. Open the UI and confirm one message. Do not claim Mailtrap QA suites or production deliverability.
- MailHog is unmaintained — do not publish it as the path. Production send stays on /stacks/plunk-newsletter.
- Write AGENT_PROMPT.md.
```

## FAQ

### Is this Postmark?

No. Production transactional send stays on /replace/postmark. This page is a staging catch inbox.

### Why not MailHog?

MailHog is unmaintained. Mailpit is the MIT catcher that still gets commits.

### Are these free?

Mailpit is MIT. You pay hosting. Template users never pay c17.

Source: https://c17.io/stacks/mailpit-smtp