SimBLE Playground

a free-form Rhai editor — the script is the Bluetooth device starting…

netsim is not reachable

Could not reach netsim at localhost:7681 — is netsimd running with its WebSocket frontend enabled? This page is served from the cloud, but the Bluetooth scene runs on your machine: the wasm build of SimBLE in this tab connects to a local netsimd over ws://localhost:7681. Start it with:

netsimd --logtostderr --no-shutdown --ws-port 7681

Needs the canary-channel emulator (see the README's Testing Against netsim section). You can still edit and Run scripts offline — the live viewer works without netsim; the socket only carries advertising and notifications when it's reachable. Tip: open the scanner in a second tab to watch your device on the air.

Live device

advertising as
—
connection
—
subscription
—

Press Run to build the device.

Output

Ready. Edit the script and press Run.

The viewer renders whatever GATT structure the running script builds — every service and characteristic, with properties, live values, and subscription state from the wasm stack's real attribute database. If the script defines fn tick(server, t) it runs ~10×/sec (t = seconds since Run) so values can animate.