Keep an account key on your server. Send it in the Authorization header as a Bearer key. An owner key reaches owner operations; a helper key reaches only its allowed operations.
See keys.json and each operation entry for access.
Practice keys
Create a practice key to check request formats. Its answers are marked as practice results. It does not place calls, send messages, charge a card, use minutes, or change your account.
A practice key sends the same POST /v1/ops/{operation-name} JSON as any key. A valid request is answered { "result": { "test": true, "operation": "<name>", "result": "stand_in" }, "request_id" }: a check of the request's shape only, not what the operation would answer. A mistake in the request gets the ordinary error.
Refusals, by reason:
test_key_forbidden(403): A practice key can use operations only.customer_test_mode_off: Customer practice keys are unavailable right now.key_limit(409): This account has reached its key limit. Revoke an unused key before creating another.