Try it out makes REAL calls against the live API. Click Authorize and paste an API key (2m_live_…) — without one you will get 401. You only ever see results your key is allowed to produce: a send-only mailbox key reaches POST /messages and GET /messages/{id}, nothing else. Keys are created in the panel under Settings → API keys once you are signed in. No account yet? Read the overview.
Building in PHP? The official SDK wraps every endpoint on this page, verifies webhook signatures for you, and turns each error code into its own exception — github.com/JaanTeam/2mail-php-api (composer require jaanbv/2mail-php-api).