Open Data API
All communication with the API is done through HTTPs, and errors are communicated through HTTP response codes. Available response types include JSON, XML, and CSV, which are selectable by the "extension" (.json, etc.) on the API endpoint or through content-negotiation with HTTP Accepts headers.
If you receive a 500 response from your API query it is most likely due to memory exhaustion. You may see a "Temporarily Unavailable" message. Make sure you include a limit appropriate to the speed of your connection, HTTP calls will time out if set too high and payloads for high limits can be very large. Complex queries should include a smaller limit value. Use the limit and offset parameters to iterate through result sets that are larger than the row limit when running queries against the datastore API.