Browser origins
The Worker has an explicit origin allowlist. A successful terminal request does not prove an arbitrary browser origin may read the same response. CORS is not authentication. Do not expand the allowlist simply to make an embedded example work. This docs site disables the API playground so readers do not accidentally submit forms, subscribe addresses, or rely on unsupported browser origins.Write requests
Same-origin JSON validation, body limits, and endpoint-specific rules apply to website forms. Newsletter confirmation, unsubscribe, and verified data-request actions require explicit POST operations. Opening a GET link must not change those states.Rate limits and retries
The gateway, newsletter routes, and owner-only mail generation do not have one universal quota. A429 may include Retry-After; honor it and bound retries. Do not automatically repeat an ambiguous contact submission.

