I Built a Chrome Extension to Track AI Token Usage — Here's How It Works

Six weeks ago I got cut off mid-debugging session by Claude's rate limit with no warning. Two hours of context gone. I started looking for a tool that would show me how close I was before it happened. Nothing existed that worked across more than one platform without requiring an API key.

So I built one.

TokenPulse is a Chrome extension (MV3) that injects a live token bar above the input box on Claude, ChatGPT, Gemini, DeepSeek and Grok. It tracks context window usage, rate limits, cost estimates, and daily history — all from your existing browser session, no API key required.

Here's how it works technically.

Architecture overview

I Built a Chrome Extension to Track AI Token Usage — Here's How It Works

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