I use WASM extensively in my OSS work with Filestash (https://github.com/mickael-kerjean/filestash ) in 3 main areas:

1. to create web versions of applications that are traditionally desktop only to render things like Parquet, PSD, TIFF, SQLite, EPS, ZIP, TGZ, and many more, where C libraries are often the reference implementations. There are almost a hundred supported file formats, most of which are supported through WASM: https://github.com/mickael-kerjean/filestash?tab=readme-ov-f...

2. to create plugins that extend the core application. As of today, you can add your own endpoint or middleware in Filestash, package it with its own manifest, and run server-side code in a constrained environment. For example, there is a libreoffice wasm edition that can run from your browser but requires a couple HTTP headers to be sent by the server to work so the plugin has this bit that run server side to add those HTTP headers: https://github.com/mickael-kerjean/filestash/blob/master/ser...

3. in the workflow engine to enable people to run their own code in actions while ensuring they can't fuck everything up