Some backends (see backends summary) support streaming bodies. If that’s the case, you can set a stream of the supported type as a request body using the streamBody method, instead of the usual body method.


Here, streaming refers to (usually) non-blocking, asynchronous streams of data. To send data which is available as an InputStream, or a file from local storage (which is available as a File or Path), no special backend support is needed. See the documenttation on setting the request body.

For example, using the akka-http backend, a request with a streaming body can be defined as follows:

import com.softwaremill.sttp._
import com.softwaremill.sttp.akkahttp._

import akka.util.ByteString

val source: Source[ByteString, Any] =   ...



A request with the body set as a stream can only be sent using a backend supporting exactly the given type of streams.