Sample: wasi:http in Kotlin

This example demonstrates an early prototype of component model support in Kotlin. In particular, the structure of the bindings is subject to change and is certainly not final.

Building

Requirements

This project requires make, git, and sufficiently recent versions of a JDK, cargo and wasm-tools.

To run the final component, a sufficiently recent version of wasmtime is also required.

cargo --version
# cargo 1.93.1 (083ac5135 2025-12-15)

wasm-tools --version
# wasm-tools 1.244.0 (d4e317f22 2026-01-06)

wasmtime --version
# wasmtime 41.0.1 (c30fce86b 2026-01-26)

javac --version
# javac 21.0.10
# but most likely, JDK 17 should be sufficient.

Non-requirements

A specific Kotlin compiler version is already selected in the Gradle config and does not need to be installed manually.

Neither wit-bindgen nor wit-deps/wkg are required to be pre-installed, as wit dependencies are already fully resolved, and the required wit-bindgen fork is cloned and built manually.

make command layout

Simplest "do everything and run immediately":

make # or make setup-and-run

More granular:

make setup

is always required in order to clone the aforementioned wit-bindgen fork and build it.

Then

make run

compiles and runs, while

make compile

only compiles.

Development and production targets

Some targets have both -dev (aka development) and -prod (aka production) variants, for example run-dev / run-prod and compile-dev / compile-prod.

When a shorter target name is available, such as run or compile, it defaults to the production variant.

Use the development variant for a faster edit-build-run loop, as it doesn't do heavy optimizations and supports incremental compilation. Use the production variant for final builds, as it is optimized for smaller output size and better runtime performance.