What's the difference between Instant and Convex?
We both offer a real-time queries out of the box. I am not 100% sure, I but think Convex also set up a multi-tenant database; so they can offer a good number of free projects well.
The way I would differentiate Instant:
With Convex you write your queries as Javascript functions. This means you have to do joins for example imperatively. With Instant, you can write queries declaratively.
As of today Convex doesn't work offline, and you have to write optimistic updates manually. Instant can run offline and comes with optimistic updates out of the box.
Both Convex and Instant support files out of the box. But with Instant you can write CASCADE delete rules, and you also get other services, like presence and streams.