Submit a lead

Submit a lead in any shape. Recommended fast-path keys: name (or first_name + last_name), phone, email. All other keys are preserved on the lead and feed overview generation. Bodies must be UTF-8 encoded. Payloads with no data at all (empty body, empty object, or a form whose fields are all blank) are rejected with 400 empty_payload; anything else is accepted, with warnings flagging missing standard fields. Requires a per-integration API key in X-API-Key. Bodies are capped at 1 MB and requests are rate-limited per integration. A 202 means the lead was durably stored; senders should retry on 5xx responses and on timeouts or connection failures where no response was received.