Scala 2, Scala 3; JVM, JS & Native

Tapir is available for Scala 3.3+, Scala 2.13 and Scala 2.12, on the JVM, JS and Native platforms.

Note that not all modules are available for all combinations of the above. This specifically applies to Scala.JS and Scala Native, where support is limited. The JVM modules require Java 11+, with a couple of exceptions, which require Java 21+ - this is marked in the documentation.

In the documentation & examples

The documentation & examples are written & compiled using Scala 3. To compile example code with Scala 2, some adjustments might be necessary:

For wildcard imports, use _ instead of *, e.g. instead of import sttp.tapir.*, use import sttp.tapir._
For the main method, instead of @main, use an object MyApp extends App, e.g.:

// in Scala 3:
@main def myExample(): Unit = /* body */

// in Scala 2:
object MyExample extends App {
  /* body */
}

Instead of given definitions, use implicit val or implicit def (for codecs, schemas etc.). E.g.:

// in Scala 3:
given Schema[MyType] = Schema.derived

// in Scala 2:
implicit val myTypeSchema: Schema[MyType] = Schema.derived

Use curly braces around class & method definitions. E.g.:

// in Scala 3:
class MyClass:
  def myMethod(): Unit =
    val z = 2
    z + 2

// in Scala 2:
class MyClass {
  def myMethod(): Unit = {
    val z = 2
    z + 2
  }
}

Scala 2.12

Partial unification is now enabled by default from Scala 2.13. However, if you’re using Scala 2.12 or older, and don’t have it already, you’ll want to to enable partial unification in the compiler (alternatively, you’ll need to manually provide type arguments in some cases). In sbt, this is:

scalacOptions += "-Ypartial-unification"