Convex

Convex is a reactive backend: database plus server functions, all in TypeScript. The interesting bit is that the function interface is the API. There’s no separate REST or GraphQL layer to keep in step, and clients subscribe to queries that update live.

Why I like it for side projects

I’ve used it for a couple of Expo apps built with coding agents, and it suits that style of work well:

• One typed contract end to end. Generated code on the client and the server agrees, because both come from the same function signatures. Agents make fewer integration mistakes when the types do the checking.
• Live data for free. Reactive queries mean no hand-rolled WebSocket plumbing for simple real-time features.
• It doesn’t box you in. You can start with “let the backend mostly write itself” and still grow into a serious back end later.

Trade-offs

It’s a hosted platform with its own data model, so you’re trading some portability for speed. For prototypes and personal apps that’s a good deal; for a regulated system I’d want to read the self-hosting and data-residency story carefully first.

Related: MSW (Mock Service Worker) · What Makes an AI Agent