About LoadLine Web Runner

LoadLine Web Runner is a performance testing tool for Chromium-based browsers on Android. Powered by the open-source Crossbench benchmarking framework running in WebAssembly, it allows running reproducible, automated browser benchmarks directly from the web without complex local environment setup.

Key Features & Workflow:

  • Direct Device Control: Connects to Android devices over USB using the WebUSB API without requiring a local ADB installation.
  • Deterministic Replay: Replays realistic web browsing scenarios using recorded Web Page Replay (WPR) archives to eliminate live-network variance.
  • Client-Side WASM Engine: Executes Crossbench benchmark logic and Perfetto Trace Processor hermetically in the browser.

Google Account & Cloud Storage Integration:

This application connects to Google Cloud Storage to download recorded WPR archive files (gs://...) required to execute benchmarks. Signing in with Google is used exclusively to request read-only access (https://www.googleapis.com/auth/devstorage.read_only) to stream and cache authorized archive files locally in your browser (IndexedDB). No personal data, credentials, or browsing telemetry are stored or transmitted to external servers. For more details, see our Privacy Policy.

1. USB Device Connection

Enable USB debugging on the device, connect it using a USB cable, and accept the "Allow USB debugging?" prompt on the device screen when connecting. If a local ADB server is running on your computer, stop it first (adb kill-server) so the browser can claim the USB interface.

Status: Initializing...

Initializing web runner modules...

2. Benchmark Variant & WPR Archive

Archive is not cached locally. If you haven't requested access yet, please fill out the access request form (only required once), then click Download to authorize and fetch the archive.

3. Crossbench Benchmark Execution

⚠️ Warning: All user data (bookmarks, history, signed-in accounts, etc.) for the selected browser package will be cleared before the run. Consider installing a separate Chrome package (Beta, Dev, or Canary) dedicated to running this benchmark.

4. Benchmark Progress

Ready to run 0%
For automation and detailed trace analysis, consider using the command-line version of the benchmark. See the LoadLine 2 README for details.
Initializing...
Loading web runner modules & environment...