Most software is still single-player. One person makes a change, everyone else refreshes and hopes they're looking at the current version. Polynomial fixes that. It's the layer you drop into a product you've already built to make it feel like other people are in it, and it takes an afternoon, not a rewrite.

It does three things.

Presence. See who else is here. Cursors move across the page with names attached, so you can tell who's reading the same paragraph, who's editing the thing you were about to edit, who just joined. None of it is stored. Close the tab and you're gone from the room, which is what anyone would expect.

Storage. The shared state that has to survive. Two people type into the same field at the same moment and both edits land. No last-write-wins, no lost paragraph, no dialog telling you someone else has the file open. Reload the page and everything is where you left it.

Events. The small signals that make a space feel occupied. A reaction, a nudge, a heads-up that something finished. Everyone in the room gets it, nothing is written down.

Links:

Website: https://polynomialhq.live
React SDK: https://www.npmjs.com/package/@polynomialhq/react
Node SDK: https://www.npmjs.com/package/@polynomialhq/server