Two ways to see it, and one honest caveat.
The browser sandbox is live now; the hosted demo arrives with the plugin's launch. Here is exactly what each one does and doesn't show — stated up front, so the demos never oversell.
WordPress Playground sandbox
A real WordPress running locally in your browser tab via WebAssembly, pre-seeded with content and a task queue. Nothing to install, nothing sent to a server, resets on refresh.
The caveat: Playground's sandbox has no loopback networking, so the dashboards, Task Inspector and settings are fully real and clickable — but background execution itself cannot run there. For proof the engine works, the benchmarks are the place to look.
Loads in your browser tab. First load downloads WordPress (~10 MB) — give it a moment.
Live site with a spawn feed
A real WordPress site where background execution genuinely happens, with a live feed of worker spawns — timestamps, durations, outcomes — streaming as they occur. Numbers that move while you watch, irregular the way real data is.
14:02:11 spawn auto 42ms ok 3 due 14:02:44 spawn auto 38ms ok 1 due 14:03:09 yield housekeeping db contention 14:03:52 spawn checkout 51ms ok 2 due
Status: ships at launch · resets hourly · read-only