We're both all in on extensible software powered by WebAssembly, but the scope and domains differ.

Suborbital is more of a turnkey / batteries-included service that handles the full lifecycle of extending SaaS applications with user-defined plugins. So it includes a web-based editor widget, a module builder service, storage and compute, administrative dashboards, etc.

Extism, from my lay understanding, is more tightly scoped toward being a great library for running WebAssembly modules, in the same way you might embed a Lua runtime into an application for user scripting.

Another big difference is that you can use all of Extism right now. Suborbital's hosted platform is still in closed beta :) (Waitlist at https://form.typeform.com/to/DHxjRGKx)