> For the complete documentation index, see [llms.txt](https://docs.asters.ai/api/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.asters.ai/api/extra/http-responses.md). # HTTP responses The API returns HTTP responses on each request to indicate the success or otherwise of API requests. \ The codes listed below are often used, and the API may use others.

Code	Response	Description
`400`	Bad Request	General client error, possibly malformed data.
`401`	Unauthorized	The API Key was not authorized (or no API Key was found).
`402`	Payment Required	The API is not available on your current plan.
`403`	Forbidden	The request is not allowed.
`404`	Not Found	The resource was not found.
`405`	Method Not Allowed	The resource does not accept the HTTP method.
`406`	Not Acceptable	The resource cannot return the client's required content type.
`408`	Request Timeout	The server would not wait any longer for the client.
`409`	Conflict	Multiple existing users match this email address - must be more specific using user_id
`415`	Unsupported Media Type	The server doesn't accept the submitted content-type.
`422`	Unprocessable Entity	The data was well-formed but invalid.
`429`	Too Many Requests	The client has reached or exceeded a rate limit, or the server is overloaded.
`500` `502` `503` `504`	Server errors	Something went wrong with Asters's servers. These responses are most likely momentary operational errors (e.g. temporary unavailability), and, as a result, requests should be retried once.