Authentication
Send your API key with every request.
Your key
Create keys on API keys in your account. Keys start with chk_. Make as many as you need, and revoke any of them there.
Sending it
Send it as a Bearer token. Anthropic clients can send it as x-api-key instead.
Authorization: Bearer chk_your_keyName your agent
An agent can register its name on the key it uses. Your account then shows its usage under that name. Register an agent
Without a key
Most paid endpoints can also be paid per call with x402. An unpaid call answers 402 with its price. Messages, streaming, and Smart Router need a key. Pay per call