---
title: "Email Testing for Developers - SMTP Labs, Inc."
canonical_url: "https://smtp.dev/"
last_updated: "2026-04-24T01:53:39.814Z"
meta:
  description: "Email testing for developers. SMTP in, IMAP/API out. Inspect headers, MIME, raw source. No servers to run."
  "og:description": "Email testing for developers. SMTP in, IMAP/API out. Inspect headers, MIME, raw source. No servers to run."
  "og:title": "Email Testing for Developers"
---

smtp.dev

# Email Testing for Developers

Test emails like you debug code. SMTP in, IMAP/API out. Inspect headers, MIME and body. No servers, no setup, no cleanup.

[Get Started](https://smtp.dev/signup/)

## **SMTP, IMAP, POP3**

Your existing mail clients work out of the box. No vendor SDK, no lock-in.

- Point an MX record, create an account, start testing. No setup wizard, no 50-page guide.
- Accounts, messages, domains, tokens. API-first.
- Headers, MIME tree, raw RFC 5322. See exactly what arrived.

![SMTP, IMAP and POP3 protocol support](https://smtp.dev/protocols.jpeg)

## **After delivery**

Check what arrived in the UI or wire it into CI.

- HTML preview, text, headers, raw source. Plus SPF/DKIM/DMARC results via API.
- Standard SMTP - any CI that sends email works. GitHub Actions, Jenkins, GitLab CI, whatever you use.
- No TTL, no auto-purge. Emails stay until you delete them.

![Email message preview with headers, HTML and raw source](https://smtp.dev/preview.jpeg)

## **Features**

**Custom Domains**

Bring your own domains. Add as many as you need.

**Unlimited Accounts**

As many inboxes as you need. No caps.

**Unlimited Messages**

No limits on sent or received messages.

**Sandboxed**

Every email stays in the sandbox. Nothing reaches a real recipient.

**SPF, DKIM, DMARC**

SPF, DKIM, DMARC checks on every inbound message. Results in the API.

**Persistent Storage**

Every email stored until you delete it. Nothing expires.

**REST API**

Accounts, messages, domains, tokens. All over REST.

**Real-time Updates**

New messages pushed via SSE. No polling.

**Catch-All & Aliasing**

Wildcard accounts and plus-sign addressing. Capture everything or route by tag.

## **Start testing**

Sign up, add a domain, receive your first test email.

[Get Started](https://smtp.dev/signup/)