ClientSideTools Privacy-First Browser Tools

BroadcastChannel Debugger

BroadcastChannel messages are silent by design. This debugger subscribes to any channel on the current origin, logs every sent and received message live, and lets you inject test payloads — perfect for verifying multi-tab sync without touching your app code.

PWA & Browser Storage Local processing Messages stay in the origin's memory. Nothing is uploaded.

Tool interface

Subscribe

Send test message

Message log

Introduction

Multi-tab apps use BroadcastChannel to sync state, but a dropped or malformed message gives no feedback. This debugger makes the invisible message stream visible and testable.

How it works

  • Creates a listener BroadcastChannel per subscribed name.
  • Logs incoming MessageEvents with timestamps.
  • Uses a separate sender instance so you can see both send and receive.
  • Formats JSON payloads and supports live filtering.

Privacy

All messaging stays within the origin's memory via the BroadcastChannel API. No data leaves the browser. No account, no API key.

Limitations

  • No history — messages before subscription are not captured.
  • Channel names can't be enumerated automatically.
  • The BroadcastChannel API is unavailable in some older browsers.

FAQ

Does BroadcastChannel work across different origins?

No. BroadcastChannel only delivers messages between browsing contexts of the same origin.

Are my messages uploaded?

No. Everything stays in the origin's memory.

Related tools

Version and changelog

  • Version: 1.0.0
  • Last updated: August 12, 2026
  • Changelog: Initial production release.