Quickstart

1. Create a key

Keys are scoped, can be pinned to a single domain and an IP allowlist, and are shown exactly once. Start with a test key — test sends need no verified domain, consume no quota, and produce real webhook events on a realistic delay curve.

export MAILHAAP_API_KEY="mh_test_a1b2c3d4e5f6g7h8i9j0k1"

2. Send

curl -X POST https://api.mailhaap.com/v1/emails \
  -H "Authorization: Bearer $MAILHAAP_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: quickstart-1" \
  -d '{
    "from": "You <[email protected]>",
    "to": ["[email protected]"],
    "subject": "It works",
    "html": "<p>Hello from MailHaap</p>"
  }'

You get a 202 with a message id. The send itself happens in a worker — the API never blocks on the provider.

{
  "id": "msg_01J8XQ7M2K9PQRSTUV",
  "status": "queued",
  "created_at": "2026-08-21T16:04:11Z"
}

3. Watch what happened

Every message carries a trace id that is queryable in the dashboard, so “why did this email not arrive” is answerable from the message id alone. The simulator addresses below produce each outcome deliberately, so you can prove your bounce and complaint handling works before a real bounce proves it does not.