200 OK: On success, the appropriate data will be returned with the HTTP status code "200 OK". This data may be XML or some other format (like PNG, GIF or JPEG), but as long as the status code indicates success, they should be there.
203 Non-Authorative Information: The product version you are attempting to use is deprecated. Please consult the product documentation page for information on how to use the upgraded product. Deprecated products are EOL's after a certain period of time - this date is available in the product documentation
304 Not Modified: Client Side Caching is supported on our API servers, and requires the use of the if-modified-since directive to be sent in the client request header. For more information, please consult the http protocol specification at http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html for more information and an example of how to correctly send this request
400 Bad Request: On error, the HTTP status code "400 Bad request" is returned along with an error message formatted as HTML. Other 4XX-codes may be added in the future to differentiate errors. In other words, a client expecting binary data (like images) should not attempt to parse, decode or use the data returned to it if it got a 4XX code.
401 Unauthorized: This indicates that you are trying to access a resource which you are not authorized to. Typical examples would be restricted products (e.g. satellite images) or administrative services.
403 Forbidden: This usually means you have been blacklisted due to a violation of our Terms of Service. On newer products like Locationforecast/2.0 it can also mean that you have been denied service because of failure to identify yourself in the User-Agent header.
404: If the request is OK as such, but the product handler does not have any data to offer, you will normally receive a "404" code. However, these are cases where empty response data (ie. an XML document with no real content) do make sense. In these cases, it can be impossible for the API to see if the input data it gets from the weather models is empty because of an error, or because it really should be empty.
422 Unprocessable Entity: The 422 status code might be returned when the request is syntactically correct, but the semantics of the specified url parameters make it impossible to return data. E.g when you specify a location outside the supported geographical area for the product. (Note: In hindsight this is probably not correct usage of 422 as it is designed for WebDAV, but sometimes it is more important to be consistent than correct.)
429 Too Many Requests: The 429 status code indicates that the user has sent too many requests in a given amount of time ("rate limiting"). Our Terms of Service state that over 20 requests/second is defined as heavy traffic, which is not allowed without permission.
499 Client Closed Request: The HTTP status code "499 Client Closed Request" is actually a client error, indicating that the client terminated the connection before the response was finished (presumably due to a timeout).
500 Internal Server Error: An unspecified error in the API itself. Could possibly indicate a bug in the code (horror!), but more likely a deployment or server problem.
502 Bad Gateway: The API could not fetch data from the backend, either from disk or one of several internal webservices.
503 Service Unavailable: The service is currently not operational or functioning properly. Examples include a radar site being down, or a service is not configured.
504 Gateway Time-out: Some backend service took to long to respond to the API. This is usually caused by heavy traffic.
