Core concepts
Sandbox & test mode
Build and test end-to-end without sending real mail — always free.
A rm_test_… key runs every request through the full pipeline — validation, suppression, rendering, events — but never delivers and never bills. Use it in development and CI to exercise real code paths safely.
- Test-mode messages appear in the dashboard's Test inbox so you can preview exactly what would have gone out.
- Webhooks still fire for test sends, so you can verify your handlers.
- Sandbox sends are free forever and don't count toward any quota.
tipPoint your CI's ROOTMAIL_API_KEY at a test key. Your test suite can assert on real responses without emailing anyone.