We initially launched Cloudflare Workers with support for JavaScript and languages that compile to WebAssembly, such as Rust, C, and C++. Since then, Cloudflare and the community have improved the usability of Typescript on Workers. But we haven’t talked much about the many other popular languages that compile to JavaScript. Today, we’re excited to announce support for Python, Scala, Kotlin, Reason and Dart.

You can build applications on Cloudflare Workers using your favorite language starting today.

Getting Started

Getting started is as simple as installing Wrangler, then running generate for the template for your chosen language: Python, Scala, Kotlin, Dart, or Reason. For Python, this looks like:

wrangler generate my-python-project https://github.com/cloudflare/python-worker-hello-world

Follow the installation instructions in the README inside the generated project directory, then run wrangler publish. You can see the output of your Worker at your workers.dev subdomain, e.g. https://my-python-project.cody.workers.dev/. You can sign up for a free Workers account if you don’t have one yet.

That’s it. It is really easy to write in your favorite languages. But, this wouldn’t be a very compelling blog post if we left it at that. Now, I’ll shift the focus to how we added support for these languages and how you can add support for others.

How it all works under the hood

Language features are important. For instance, it’s hard to give up the safety and expressiveness of pattern matching once you’ve used it. Familiar syntax matters to us as programmers.

You may also have existing code in your preferred language that you’d like to reuse. Just keep in mind that the advantages of running on V8 come with the limitation that if you use libraries that depend on native code or language-specific VM features, they may not translate to JavaScript. WebAssembly may be an option in that case. But for memory-managed languages you’re usually better off compiling to JavaScript, at least until the story around garbage collection for WebAssembly stabilizes.

I’ll walk through how the Worker language templates are made using a representative example of a dynamically typed language, Python, and a statically typed language, Scala. If you want to follow along, you’ll need to have Wrangler installed and configured with your Workers account. If it’s your first time using Workers it’s a good idea to go through the quickstart.

#cloudflare workers #serverless #serverless week #javascript #python #wrangler #scala