Comment by cyberax

Our webapp is nearly instant, and it's built on raw React with some sprinkling of Tanstack (their Local Collection DB is a masterpiece).

And our stack is intentionally client-heavy. We proactively synchronize all the relevant data and keep it in IndexedDB, with cross-tab coordination. The server is used only for mutating operations and for some actions that necessarily require server-side logic.

The issue with dependencies and the package size if valid, but it's also really not a big deal for performance unless you go WAAAY overboard. Or use crappy dependencies (Clerk, I'm looking at you, 2.5Mb for an auth library!?!?).

As for hydration, I found that it often slows down things. It's a valid approach when you're doing query-based apps, but when you have all the data locally, it just makes little sense. It also adds a ton of complexity, because now your code has to automagically run in multiple environments. I don't think it can really ever work reliably and safely.