sttp: the Scala HTTP client you always wanted!

This is the development version of the upcoming sttp client 4. For the current stable version, see sttp 3 on GitHub and its documentation.


sttp client is an open-source library which provides a clean, programmer-friendly API to describe HTTP requests and how to handle responses. Requests are sent using one of the backends, which wrap lower-level Scala or Java HTTP client implementations. The backends can integrate with a variety of Scala stacks, providing both synchronous and asynchronous, procedural and functional interfaces.

Backend implementations include the HTTP client that is shipped with Java, as well as ones based on akka-http, pekko-http, http4s, OkHttp. They integrate with Akka, Monix, fs2, cats-effect, scalaz and ZIO. Supported Scala versions include 2.12, 2.13 and 3, Scala.JS and Scala Native; supported Java versions include 11+.

Here’s a quick example of sttp client in action:

import sttp.client4._

val query = "http language:scala"
val sort: Option[String] = None

// the `query` parameter is automatically url-encoded
// `sort` is removed, as the value is not defined
val request = basicRequest.get(

val backend = DefaultSyncBackend()
val response = request.send(backend)

// response.header(...): Option[String]

// response.body: by default read into an Either[String, String] 
// to indicate failure or success 

For more examples, see the usage examples section. To start using sttp client in your project, see the quickstart. Or, browse the documentation to find the topics that interest you the most! ScalaDoc is available at

Other sttp projects

sttp is a family of Scala HTTP-related projects, and currently includes:

  • sttp client: this project

  • sttp tapir: Typed API descRiptions

  • sttp model: simple HTTP model classes (used by client & tapir)

  • sttp shared: shared web socket, FP abstractions, capabilities and streaming code.

  • sttp apispec: OpenAPI, AsyncAPI and JSON Schema models.

Third party projects:

  • sttp-oauth2: OAuth2 client library for Scala

  • sttp openai: Scala client wrapper for OpenAI (and OpenAI-compatible) API. Use the power of ChatGPT inside your code!

Try sttp client in your browser!

Check out & play with a simple example on Scastie!


Development and maintenance of sttp client is sponsored by SoftwareMill, a software development and consulting company. We help clients scale their business through software. Our areas of expertise include backends, distributed systems, machine learning, platform engineering and data analytics.

Commercial Support

We offer commercial support for sttp and related technologies, as well as development services. Contact us to learn more about our offer!

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