frappe-errors-api

Use when debugging or handling API errors in Frappe/ERPNext v14/v15/v16. Prevents silent failures and wrong HTTP status codes in REST endpoints. Covers 401 Unauthorized (wrong token format, expired OAuth), 403 Forbidden (missing @whitelist, allow_guest needed), 404 Not Found (wrong endpoint URL), 417 Expectation Failed (validation via frappe.throw), 500 Internal Server Error, CORS issues, CSRF token missing/invalid, rate limit exceeded (429), file upload failures, JSON parse errors in request/response, webhook delivery failures, and timeout on long operations. Keywords: API error, 401, 403, 404, 417, 429, 500, CSRF, CORS, REST,, API call fails, 403 forbidden, CORS error, token expired, endpoint not found, webhook not received. whitelist, webhook, rate limit, file upload, authentication token.