At the moment, it seems like they're concentrating on using V8 isolates. In the article, there's a good diagram of why: an isolate is able to share so much betw

At the moment, it seems like they're concentrating on using V8 isolates. In the article, there's a good diagram of why: an isolate is able to share so much between different applications. Even with NativeAOT, you're still launching an entire program that has to load everything into memory and execute. In some ways, they're using V8 isolates the way that mod_php was used back in the day. One reason PHP became so dominant was because PHP was cheap and easy to deploy for small websites. Because the PHP runtime contained 90% of what a person wanted to do with PHP, your PHP code might be a small amount of code that mostly just called standard library functions like `mysql_query()`. If you were running a shared hosting service, you could have huge numbers of people running on the same box because every PHP script would be sharing a single instance of the PHP standard library - and that standard library was fast and written in C. If you wanted to offer Python hosting, each Python app would be duplicating the standard library they were using in memory and also needing lots of web packages that aren't part of the standard library (like a database package). So a minimal Python application was using tons more RAM because it wasn't sharing most of the code with everyone else on the box. Even with NativeAOT, you're still duplicating a lot when running many different C# projects - as is the case with Go, Java, Ruby, etc. V8 isolates are this case where they tend to be lighter weight because so much can be shared between different users in the system. In fact, the reason they're supporting Python is because Pyodide (Python interpreter in WASM) allows for dynamic linking. It means they can have a single Pyodide interpreter in memory that's shared by all the Python workers on the same box. Likewise, they can also share Python libraries that two different people on the same box might be using. They note that most languages that target WASM don't support dynamic linking and that the only way they can provide Cloudflare Workers at the price point they offer is because those Workers can share so much rather than duplicating and using more memory for each user. If you really want C# on Workers, C# does support WASM.