Completely agree on this.

Regarding cold-starts, I strongly believe V8 snapshots are perhaps not the best way to achieve fast cold starts with Python (they may be if you are tied to using V8, though!), and will have wide side effects if you go out of the standards packages included on the Pyodide bundle.

To put some perspective: V8 snapshots are storing the whole state of an application (including it's compiled modules). This means that for a Python package that is using Python (one wasm module) + Pydantic-core (one wasm module) + FastAPI... all of those will be included in one snapshot (as well as the application state). This makes sense for browsers, where you want to be able to inspect/recover everything at once.

The issue about this design is that the compiled artifacts and the application state are bundled into one piece artifact (this is not great for AOT designed runtimes, but might be the optimal design for JITs though).

Ideally, you would separate each of the compiled modules from the state of the application. When you do this, you have some advantages: you can deserialize the compiled modules in parallel, and untie the "deserialization" from recovering the state of the application. This design doesn't adapt that well into the V8 architecture (and how it compiles stuff) when JavaScript is the main driver of the execution, however it's ideal when you just use WebAssembly.

This is what we have done at Wasmer, which allows for much faster cold starts than 1 second. Because we cache each of the compiled modules separately, and recover the state of the application later, we can achieve cold-starts that are a magnitude faster than Cloudflare's state of the art (when using pydantic, fastapi and httpx).

If anyone is curious, here is a blogpost where we presented fast-cold starts for the application state (note that the deserialization technique for Wasm modules is applied automatically in Wasmer, and we don't showcase it on the blogpost): https://wasmer.io/posts/announcing-instaboot-instant-cold-st...

Note aside: congrats to the Cloudflare team on their work on Python on Workers, it's inspiring to all providers on the space... keep it up and let's keep challenging the status quo!