# Server options

Each interpreter can be configured using an options object, which includes:

• how to create a file (when receiving a response that is mapped to a file, or when reading a file-mapped multipart part)

• if, and how to handle exceptions (see error handling)

• if, and how to log requests (see logging & debugging)

• how to handle decode failures (see error handling)

To use custom server options pass them as an argument to the interpreter’s apply method. For example, for AkkaHttpServerOptions and AkkaHttpServerInterpreter:

import sttp.tapir.server.interceptor.decodefailure.DecodeFailureHandler
import sttp.tapir.server.akkahttp.AkkaHttpServerOptions
import sttp.tapir.server.akkahttp.AkkaHttpServerInterpreter
import scala.concurrent.ExecutionContext.Implicits.global

val customDecodeFailureHandler: DecodeFailureHandler = ???

val customServerOptions: AkkaHttpServerOptions = AkkaHttpServerOptions
.customiseInterceptors
.decodeFailureHandler(customDecodeFailureHandler)
.options

AkkaHttpServerInterpreter(customServerOptions)


## Hiding authenticated endpoints

By default, if authentication credentials are missing for an endpoint which defines authentication inputs, a 401 Unauthorized response is returned.

If you would instead prefer to hide the fact that such an endpoint exists from the client, a 404 Not Found can be returned instead by using a different decode failure handler. For example, using akka-http:

import sttp.tapir.server.interceptor.decodefailure.DefaultDecodeFailureHandler
import sttp.tapir.server.akkahttp.AkkaHttpServerOptions
import sttp.tapir.server.akkahttp.AkkaHttpServerInterpreter
import scala.concurrent.ExecutionContext.Implicits.global

val customServerOptions: AkkaHttpServerOptions = AkkaHttpServerOptions
.customiseInterceptors
.decodeFailureHandler(DefaultDecodeFailureHandler.hideEndpointsWithAuth)
.options

AkkaHttpServerInterpreter(customServerOptions)


Note however, that it can still be possible to discover the existence of certain endpoints using timing attacks. Moreover, any 400 Bad Request response are also converted to a 404, making working the endpoint harder - there’s no feedback as to what kind of query parameters or headers might be missing or malformed.

This applies only to inputs, which fail do decode. For scenarios where the inputs decode successfully, but the authentication should fail, an error result should be returned from the security logic.