fixture.email
Start trial

~/fixture.email git:(main) start-trial

Email testing, built for agents.

Spin up real inboxes, send and receive actual email, and assert on it in your end-to-end tests — an AI-native alternative to Mailosaur that your AI coding agent can wire up on its own.

Start 15-day trial Read the docs
  • Mailosaur alternative
  • Runs in your CI
  • AI-native
agent · starter-prompt 
# paste into your coding agent
Use the fixture.email MCP to verify our signup flow:
  1. mint a mailbox
  2. trigger the signup email
  3. assert the verification link resolves

~/fixture.email --unlocks

Stop mocking email. Test the real thing.

01

Real email, actually delivered

Send and receive genuine messages, not stubs. Assert on the exact subject, body, links, and headers your users receive.

02

Deterministic, never flaky

Every mailbox is uniquely addressable and isolated, so the same test passes the same way on every run. No shared state, no cross-talk, no retry-until-green.

03

Your agent does the wiring

Point your AI coding agent at the fixture.email MCP and it mints mailboxes and drafts the assertions against your suite. No SDK to learn, no dashboard to click.

~/fixture.email --how-it-works

From signup to passing test in one paste.

  1. 01 — Start your trial One checkout 15 days free, cancel anytime.
  2. 02 — Paste the starter prompt One paste Drop the one-paste prompt into Claude Code or any MCP-aware agent.
  3. 03 — Your agent builds Tests written for you It connects to fixture.email, mints mailboxes, and writes the email assertions straight into your tests.

~/fixture.email --plain-http

Simple HTTP. Your agent speaks it natively.

http · mint → send → assert 
# 1 — mint a mailbox
POST https://send.fixture.email/api/mailboxes
  → { "mailbox": "x7k2m9", "address": "x7k2m9@fixture.email" }

# 2 — your app sends to  signup+x7k2m9@fixture.email

# 3 — assert it arrived
GET https://send.fixture.email/api/messages?mailbox=x7k2m9
  → 200 · subject "Verify your email" · 1 link  ✓

Or skip the HTTP entirely — your agent calls these through the MCP.

~/fixture.email --migrating

Everything you used Mailosaur for. Less of what you didn't.

Mailboxes, real send and receive, content and attachment assertions — the capability you already rely on. The difference is what is around it: no dashboard tax, and an agent that does the integration for you.

  • Real mailboxes, send & receive, assertions
  • Works in the CI you already run
  • Your agent writes the integration

~/fixture.email --about

Built for the agents that build with you.

fixture.email is end-to-end email testing for software teams and the AI agents that build with them: mint disposable mailboxes, send and receive real messages, and assert on the exact subject, body, links, and headers your users get. People and agents onboard the same way — get credentials and run a real email test in minutes. A developer can sign up through checkout and paste a starter prompt into their agent; an agent can pay on its own and drive the whole flow over the MCP, with no human in the loop.

~/fixture.email --pricing

One plan. Start free.

A single, simple plan with everything included. 15-day free trial — card required, cancel anytime before it ends.

card required · cancel anytime before day 15

Ship email tests your agent wrote.

Start your 15-day trial and point your agent at fixture.email.

Start 15-day trial