The gist of it is that if you update a cell, we incrementally update the spreadsheet which means we will only emit a minimal amount of changes for the cells affected by your update. The nice thing about it is that this is something that Feldera does automatically (and it would do that for any SQL that you end up writing, so it doesn't have to be a spreadsheet, but a spreadsheet is a nice example that everyone understands and knows about).

There is a more detailed explanation in this video https://www.youtube.com/watch?v=ROa4duVqoOs if you're interested what's going on under the hood -- or if you prefer reading about it we have an article series that goes over all the parts of the demo

1. Feldera SQL (gets compiled to Rust) https://docs.feldera.com/use_cases/real_time_apps/part1

2. API server (Rust/Axum hosted on fly.io) https://docs.feldera.com/use_cases/real_time_apps/part2

3. egui web Client (Rust compiled to WebAssembly) https://docs.feldera.com/use_cases/real_time_apps/part3