The main draw for me with elysia was that it maintains bun's perf benefits unlike express. When I got into the weeds of the documentation, their abstractions could use a lot of polish. The lifecycle of a request is not that clear imo and all the hooks you put into it look like hacks rather than integrations.

Elysia is sooo underrated. IMO they could improve their marketing by emphasizing they're compatible with other environments and not just Bun.

would love to see it if open source!

Not very good. The type safety thing doesn't work well when you are using it across different folders.