Status codes

To provide a (varying) status code of a server response, use the statusCode output, which maps to a value of type type tapir.model.StatusCode (which is an alias for Int). The tapir.model.StatusCodes object contains known status codes as constants. This type of output is used only when interpreting the endpoint as a server.

Alternatively, a fixed status code can be specified using the statusCode(code) output.

Dynamic status codes

It is also possible to specify how status codes map to different outputs. All mappings should have a common supertype, which is also the type of the output. These mappings are used to determine the status code when interpreting an endpoint as a server, as well as when generating documentation and to deserialise client responses to the appropriate type, basing on the status code.

For example, below is a specification for an endpoint where the error output is a sealed trait ErrorInfo; such a specification can then be refined and reused for other endpoints:

sealed trait ErrorInfo
case class NotFound(what: String) extends ErrorInfo
case class Unauthorized(realm: String) extends ErrorInfo
case class Unknown(code: Int, msg: String) extends ErrorInfo
case object NoContent extends ErrorInfo

val baseEndpoint = endpoint.errorOut(
    statusMapping(StatusCodes.NotFound, jsonBody[NotFound].description("not found")),
    statusMapping(StatusCodes.Unauthorized, jsonBody[Unauthorized].description("unauthorized")),
    statusMapping(StatusCodes.NoContent, => NoContent)(_ => ())),

Each mapping, defined using the statusMapping method is a case class, containing the output description as well as the status code. Moreover, default mappings can be defined using statusDefaultMapping:

  • for servers, the default status code for error outputs is 400, and for normal outputs 200 (unless a statusCode is used in the nested output)
  • for clients, a default mapping is a catch-all.

Server interpreters

Unless specified otherwise, successful responses are returned with the 200 OK status code, and errors with 400 Bad Request. For exception and decode failure handling, see error handling.