Common errors

Partner APIs return a stable envelope with error.code and HTTP status. Full tables: Status codes.

401 unauthorized — missing/invalid API key
403 forbidden — missing permission
400 invalid_filter_field / invalid_event / invalid_api_version — webhook registration contract
422 validation_error — malformed JSON or bad URL
429 rate_limited — slow down; honor Retry-After
502 bad_gateway — Test delivery to your URL failed