Where possible, the TwitLonger API will attempt to respond with an appropriate HTTP status code. In addition, it will send back an array of errors, each with a description of the error along with its own internal error code to help further pinpoint the issue. Currently, there will be only a single error reported at a time.
| Error code | HTTP status | Response | Description |
| 1 | 405 | Method not implemented | This is a valid endpoint for the API, just not with the request method. Check what methods the endpoint accepts. Typically, this will be for methods that may be implemented in the future. |
| 2 | 501 | Invalid endpoint for this API version | There is no resource at that endpoint for any request method at this time. Helps distinguish between endpoints that don't exist at all rather than just using the wrong request method. |
| 3 | 404 | No post found with that ID | When requesting an action on a TwitLonger post, this means the request was fine, but the post doesn't exist |
| 4 | 403 | Invalid API key | Either you haven't supplied the X-API-KEY in the request header, or the API key you supplied isn't recognised. |
| 5 | 403 | This application is not active | The API key supplied is recognised, but the application has been disabled. This would be the response if the application has been blocked. |
| 6 | 503 | This method is currently not available | This is a valid endpoint, but is currently unavailable due to maintenance or other site issue. It should return presently. |
| 7 | 403 | Banned Account | This user is currently blocked from using TwitLonger. |
| 8 | 400 | Missing parameters | The request is well formed, but some required parameters are missing or empty. Typical cause would be an empty content parameter when trying to create a new post. |
| 9 | 403 | Verification URL not acceptable | The URL supplied to verify the client via OAuth Echo does not match the list of acceptable URLs. Please check the endpoint you are supplying in the X-AUTH-SERVICE-PROVIDER header. |