Cloudflare Pages + WebAssembly

Run BGP simulations directly in the browser.

Upload an announcements CSV, choose a target ASN, and inspect the AS paths that reach it. The simulator runs in the browser and is available on fourzo.me.

Open simulator Download sample CSV
Execution Browser-based simulation

WASM lets the simulator run directly in the browser.

Inputs Announcements CSV + target ASN

Default topology and ROV datasets are bundled with the site for quick testing.

Outputs Paths at the chosen AS

Results render as a readable table and can be exported back to CSV.

Simulation inputs

Configure the run

Loading WASM engine…

Preparing the browser runtime and bundled datasets.

Results

Announcements visible at the target AS

Target ASN -
Routes found -
Topology size -

No simulation has been run yet.

Prefix AS Path Learned Via Next Hop ROV Invalid
Run a simulation to inspect the announcements that reach your chosen ASN.