For Workers specifically, there's a 1 MiB 'cliff' where you'll run into cold start times that are a little painful as you're not kept in the same hot storage as you would be with < 1 MiB. Observability is a little interesting, and by that I mean you'll run into some vague promise errors in some cases where your module is instantiated globally. If you hit a panic, requests will log that they were terminated due to a hanging Promise. Since the WASM module it was relying on has gone, and the runtime sees there are no other promises in that request's context, it just thinks it's frozen. can help demystify some of that and give you the 'real' reason as to why it happened. You can do some pretty cool stuff in WebAssembly though, both in the 'framework' of #882757739019911219 but also just a module that exports a function you call in JS (like in ). You can run a JS engine, you can use

reqwest

rather than the

fetch

in the #882757739019911219 crate, you can still use serde and whatnot, etc.