```ubuntu@ubuntu:kotlin$ compiler/cli/bin/kotlinc-...

# compiler

[ventura]

ubuntu@ubuntu:kotlin$ compiler/cli/bin/kotlinc-js

Error: Could not find or load main class org.jetbrains.kotlin.preloading.Preloader
Caused by: java.lang.ClassNotFoundException: org.jetbrains.kotlin.preloading.Preloader

[ventura]

Do I have to compile the whole project or is there a way of load the JAR files?

[udalov]

You have to compile the project (e.g. via ./gradlew dist) and then run dist/kotlinc/bin/kotlinc-js