AI Toolbar
One hundred thousand people installed a Chrome extension we built. Then they used it ten million times.
Industry: Productivity, AI Tools | Stack: Chrome MV3, TypeScript, LLM APIs, Voice Recognition | Status: Live, 70,000+ active users | Key Metric: 10M+ AI responses generated | Visit AI Toolbar | Chrome Web Store
what AI Toolbar does#
AI Toolbar puts a full AI assistant inside the browser. Not a chatbot in a new tab, not a copy-paste workflow between your browser and a separate tool. An embedded copilot that drafts emails, answers questions, summarizes content, translates text, and responds to voice commands, all without leaving the page you are on. The tagline on the site: "Do the work, without 'Doing' the Work."
It serves 70,000+ active users with both a free tier (full core features) and a premium tier at £4.20/month billed annually. Users have generated over 10 million AI responses through the extension since launch.
the scale story#
Most Chrome extensions never reach 1,000 users. 86.3% of all Chrome extensions sit below that threshold (Chrome-Stats, 2024). AI Toolbar crossed 100,000 installs at its peak.
What got it there was not any single feature. It was reliability. Extensions that break on websites people actually use get uninstalled. Extensions that slow down every page they load get uninstalled. We spent a lot of time on the unglamorous parts: graceful API rate limit handling at volume, content scripts that could extract text from arbitrary DOM structures without breaking the page, UI that felt like it belonged in the browser rather than something duct-taped on top.
The Chrome MV3 migration was the other thing. Chrome disabled all MV2 extensions in Chrome 138/139 in August 2025. Extensions built on MV2 either scrambled to rewrite or went dark. We built AI Toolbar MV3-native from day one, so when the cutover happened, our users noticed nothing. That decision, made early, saved us from a scramble that killed off a lot of competing extensions.
We are still at 70,000+ active users. The premium tier has been retaining subscribers since 2023.
what we built#
The core feature is the AI copilot. It reads the page context and generates a draft based on what you are actually doing, not a blank text field you fill yourself. If you are on a Gmail thread, it infers the context. If you are on a support platform, it reads the ticket. The idea was that writing assistance should meet you where you are, not make you context-switch.
Voice activation was harder to get right than expected. The browser's Web Speech API works, but building a voice-first interaction layer on top of it that did not feel clunky required iteration. You speak, the AI responds, and the whole exchange happens without touching the keyboard. We are happy with how it landed.
The chatbot runs open-ended AI conversations with Word and PDF export built in, which turned out to be genuinely useful for people using the extension to do research and draft deliverables. And there is a text selection tool for running AI operations inline: summarize, translate, paraphrase, extract. You highlight, you click, the output appears next to the text.
Finally, a toolbar overlay for ChatGPT itself. It sits at the top of the ChatGPT interface and adds prompt building, export tools, and workflow shortcuts that ChatGPT does not provide natively.
Architecture:
- Chrome Manifest V3 with service worker background scripts
- Content scripts for DOM interaction and text extraction across arbitrary websites
- LLM API integration with token management and rate limiting for high-volume usage
- Voice recognition layer with browser-native Web Speech API
- Side panel and popup UI rendering for a native browser feel
- Export pipeline generating Word and PDF documents client-side
results#
100,000 peak installs. 70,000 still active. 10 million AI responses generated. Premium subscribers paying since 2023.
The Chrome MV3 cutover happened and we did not lose users to it. That was the moment we were most relieved about. A lot of competing tools did not survive it.
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