Kotlin, KTor and HTMX front end demos

This page shows synchronization between browser windows. Open multiple windows to this URL to see it in action.

Go here for a lengthy blogpost about the implementation and links to code. I use HTMX, SSE and KTor to do this. It is inspired by Hamilton Greene's 1000-checkboxes

Showing: 100 000 checkboxes. SSE update batches are 333.

Full refresh: Tue, 3 Mar 2026 09:27:03 +0100

Connected browsers: 1

Max boxes: 100000

Batch size: 333

Loaded in browser: 0