Credentials
Three credentials reach the API: an account key (rlka_) that acts as you, minted at Account → API keys; a project key (rlk_) bound to one project, minted from the account key or from Integrations → AI tools; and a published site’s own key, carried in the body by page code running in a stranger’s browser. In-app routes take the signed-in session and no key at all. Every card in the reference states which one it takes, and the sample sends exactly that.
A project is the memory boundary every later call is scoped to. An account key at Editor provisions without a browser: create a project per customer or per repository, then mint the narrower keys your services hold.