With tapir, you can describe HTTP API endpoints as immutable Scala values. Each endpoint can contain a number of input and output parameters. An endpoint specification can be interpreted as:
- a server, given the "business logic": a function, which computes output parameters based on input parameters. Currently supported:
- a client, which is a function from input parameters to output parameters. Currently supported:
- documentation. Currently supported:
Depending on how you prefer to explore the library, take a look at one of the examples
or head over to the docs for a more detailed description of how tapir works! Or, use adopt-tapir to generate a tapir-based project in a couple of clicks! You can also generate a stub of a tapir-based application directly from the command line with sbt new softwaremill/tapir.g8.
- type-safety: compile-time guarantees, develop-time completions, read-time information
- declarative: separate the shape of the endpoint (the "what"), from the server logic (the "how")
- OpenAPI / Swagger integration: generate documentation from endpoint descriptions
- observability: leverage the metadata to report rich metrics and tracing information
- abstraction: re-use common endpoint definitions, as well as individual inputs/outputs
- library, not a framework: integrates with your stack
Is your company already using tapir? We're continually expanding the "adopters" section in the documentation; the more the merrier! It would be great to feature your company's logo, but in order to do that, we'll need written permission to avoid any legal misunderstandings.
Please email us at [email protected] from your company's email with a link to your logo (if we can use it, of course!) or with details who to kindly ask for permission to feature the logo in tapir's documentation. We'll handle the rest.
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import sttp.tapir._
import sttp.tapir.generic.auto._
import sttp.tapir.json.circe._
import io.circe.generic.auto._
type Limit = Int
type AuthToken = String
case class BooksQuery(genre: String, year: Int)
case class Book(title: String)
// Define an endpoint
val booksListing: PublicEndpoint[(BooksQuery, Limit, AuthToken), String, List[Book], Any] =
endpoint
.get
.in(("books" / path[String]("genre") / path[Int]("year")).mapTo[BooksQuery])
.in(query[Limit]("limit").description("Maximum number of books to retrieve"))
.in(header[AuthToken]("X-Auth-Token"))
.errorOut(stringBody)
.out(jsonBody[List[Book]])
// Generate OpenAPI documentation
import sttp.apispec.openapi.circe.yaml._
import sttp.tapir.docs.openapi.OpenAPIDocsInterpreter
val docs = OpenAPIDocsInterpreter().toOpenAPI(booksListing, "My Bookshop", "1.0")
println(docs.toYaml)
// Convert to akka-http Route
import sttp.tapir.server.akkahttp.AkkaHttpServerInterpreter
import akka.http.scaladsl.server.Route
import scala.concurrent.Future
import scala.concurrent.ExecutionContext.Implicits.global
def bookListingLogic(bfy: BooksQuery,
limit: Limit,
at: AuthToken): Future[Either[String, List[Book]]] =
Future.successful(Right(List(Book("The Sorrows of Young Werther"))))
val booksListingRoute: Route = AkkaHttpServerInterpreter()
.toRoute(booksListing.serverLogic((bookListingLogic _).tupled))
// Convert to sttp Request
import sttp.tapir.client.sttp.SttpClientInterpreter
import sttp.client3._
val booksListingRequest: Request[DecodeResult[Either[String, List[Book]]], Any] =
SttpClientInterpreter()
.toRequest(booksListing, Some(uri"http://localhost:8080"))
.apply((BooksQuery("SF", 2016), 20, "xyz-abc-123"))tapir documentation is available at tapir.softwaremill.com.
Add the following dependency:
"com.softwaremill.sttp.tapir" %% "tapir-core" % "1.8.3"Then, import:
import sttp.tapir._And finally, type endpoint. and see where auto-complete gets you!
Partial unification is now enabled by default from Scala 2.13. However, if you're using Scala 2.12 or older, then you'll need partial unification enabled in the compiler (alternatively, you'll need to manually provide type arguments in some cases):
scalacOptions += "-Ypartial-unification"Sidenote for scala 2.12.4 and higher: if you encounter an issue with compiling your project because of
a StackOverflowException related to this scala bug,
please increase your stack memory. Example:
sbt -J-Xss4M clean compilesttp is a family of Scala HTTP-related projects, and currently includes:
- sttp client: the Scala HTTP client you always wanted!
- sttp tapir: this project
- 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.
All suggestions welcome :)
See the list of issues and pick one! Or report your own.
If you are having doubts on the why or how something works, don't hesitate to ask a question on
discourse or via github. This probably means that the documentation, scaladocs or
code is unclear and be improved for the benefit of all.
In order to develop the documentation, you can use the doc/watch.sh script, which runs Sphinx using Python.
Use doc/requirements.txt to set up your Python environment with pip. If you're using Nix, you can just run nix develop
in the doc directory to set up a working shell with all the dependencies.
The core module needs to remain binary-compatible with earlier versions. To check if your changes meet this requirement,
you can run core/mimaReportBinaryIssues from the sbt console.
However, be aware that tags from the repository aren’t automatically fetched during forking; hence, the command will not operate without first fetching the tags.
After forking and cloning the repository, add the original repository as a remote:
git remote add upstream [email protected]:softwaremill/tapir.git
Fetch the tags from the upstream:
git fetch --tags upstream
The JS tests use Gecko instead of Chrome, although this causes another problem: out of memory when running JS tests for multiple modules. Work-arounds:
- run only tests for a specific Scala version and platform using
testScoped 2.13 JS(supported versions: 2.12, 2.13, 3; supported platforms: JVM, JS, Native) - test single JS projects
- use CI (GitHub Actions) to test all projects - the
.github/workflows/ci.ymlenumerates them one by one
You can test only server/client/doc/other projects using testServers, testClients, testDocs and testOther.
To verify that the code snippet in docs compile, run compileDocumentation. A full mdoc run is done during a release
(when the documentation is generated).
By default, when importing to IntelliJ, only the Scala 3/JVM subprojects will be imported. This is controlled by the ideSkipProject setting in build.sbt (inside commonSettings).
If you'd like to work on a different platform or Scala version, simply change this setting temporarily so that the correct subprojects are imported. For example:
// import only Scala 2.13, JS projects
ideSkipProject := (scalaVersion.value != scala2_13) || !thisProjectRef.value.project.contains("JS")
// import only Scala 3, JVM projects
ideSkipProject := (scalaVersion.value != scala3) || thisProjectRef.value.project.contains("JS") || thisProjectRef.value.project.contains("Native"),
// import only Scala 2.13, Native projects
ideSkipProject := (scalaVersion.value != scala2_13) || !thisProjectRef.value.project.contains("Native")
We offer commercial support for tapir and related technologies, as well as development services. Contact us to learn more about our offer!
Copyright (C) 2018-2023 SoftwareMill https://softwaremill.com.