Generating OpenAPI documentation

To use, add the following dependencies:

"com.softwaremill.sttp.tapir" %% "tapir-openapi-docs" % "0.12.0"
"com.softwaremill.sttp.tapir" %% "tapir-openapi-circe-yaml" % "0.12.0"

Tapir contains a case class-based model of the openapi data structures in the openapi/openapi-model subproject (the model is independent from all other tapir modules and can be used stand-alone).

An endpoint can be converted to an instance of the model by importing the package and calling the provided extension method:

import sttp.tapir.openapi.OpenAPI

val docs: OpenAPI = booksListing.toOpenAPI("My Bookshop", "1.0")

Such a model can then be refined, by adding details which are not auto-generated. Working with a deeply nested case class structure such as the OpenAPI one can be made easier by using a lens library, e.g. Quicklens.

Multiple endpoints can be converted to an OpenAPI instance by calling the extension method on a list of endpoints:

List(addBook, booksListing, booksListingByGenre).toOpenAPI("My Bookshop", "1.0")

The openapi case classes can then be serialised, either to JSON or YAML using Circe:

import sttp.tapir.openapi.circe.yaml._


Each endpoint corresponds to an operation in the OpenAPI format and should have a unique operation id. By default, the name of endpoint is used as the operation id, and if this is not available, the operation id is auto-generated by concatenating (using camel-case) the request method and path. This can be customised by providing an implicit instance of OpenAPIDocsOptions.

Exposing OpenAPI documentation

Exposing the OpenAPI documentation can be very application-specific. However, tapir contains modules which contain akka-http/http4s routes for exposing documentation using Swagger UI or Redoc:

"com.softwaremill.sttp.tapir" %% "tapir-swagger-ui-akka-http" % "0.12.0"
"com.softwaremill.sttp.tapir" %% "tapir-swagger-ui-http4s" % "0.12.0"
"com.softwaremill.sttp.tapir" %% "tapir-redoc-http4s" % "0.12.0"

Usage example for akka-http:

import sttp.tapir.openapi.circe.yaml._
import sttp.tapir.swagger.akkahttp.SwaggerAkka

val docsAsYaml: String = myEndpoints.toOpenAPI("My App", "1.0").toYaml
// add to your akka routes
new SwaggerAkka(docsAsYaml).routes

For http4s, use the SwaggerHttp4s or RedocHttp4s classes.