Five years of React Native at Shopify

But as a user of computers and occasional native mobile app developer, hearing "<500ms screen load times" stated as a win is very disappointing. Having your app burn battery for half a second doing absolutely nothing is bad UX. That kind of latency does have a meaningful effect on productivity for a heavy user.

Besides that, having done a serious evaluation of whether to migrate a pair of native apps supported by multi-person engineering teams to RN, I think this is a very level-headed take on how to make such a migration work in practice. If you're going to take this path, this is the way to do it. I just hope that people choose targets closer to 100ms.

When the user clicks a button, we start a server round-trip and fetch the data and do client-side parsing, layout, formatting and rendering and then less than 500ms later, the user can see the result on his/her screen.

With a worst-case ping of 200ms for a round-trip, that leaves about 200ms for DB queries and then 100ms for the GUI rendering, which is roughly what you'd expect.

RTT to nearest major metro DC should be up to 20ms (where I am it is less than half that), your DB calls should not be anything like 200ms (and in the event they are you need to show something else first), and 10-20ms is what you should assume for rendering budget of something very big. 60hz means 16ms per frame after all.

As you reach for higher percentiles, RTT and such start growing very fast.

Edit: other commenter mentioned 75% as percentile.

Also, due to layouting, a CRUD app may actually be harder to optimize per frame, than the trivial to parallelize many triangle case as seen in games.