Error Handling

The API returns standard HTTP status codes. Always check both the HTTP status code and the returncode field in the JSON response.

HTTP Status	Meaning	Recommended Action
200 OK	Success	Parse pricing_results and render to end user
400 Bad Request	Invalid request body	Check required fields and data types; fix before retrying
401 Unauthorized	Bad API key	Verify x-api-key header; do not retry automatically
422 Unprocessable Entity	Invalid field value	Validate enum values and numeric ranges before submission
429 Too Many Requests	Rate limit exceeded	Respect Retry-After header; implement exponential back-off
500 Internal Server Error	Server error	Retry up to 3× with back-off; contact support if persistent

// 401: { "returncode":401, "message":"Unauthorized: invalid x-api-key" }
// 400: { "returncode":400, "message":"loan_purpose is required" }
// 422: { "returncode":422, "message":"loan_type must be one of: Conventional, fha, VA, USDA, ARM, nonqm" }
// 429: { "returncode":429, "message":"Rate limit exceeded. Retry after 60 seconds." }
// 500: { "returncode":500, "message":"Internal server error. Contact support." }