An AI sidebar that actually works on Firefox

GlassBar is a ChatGPT-style sidebar for Firefox — technically a frosted-glass chat bar docked to the bottom of every web page. You ask about the page you're reading, and the answer streams in place, using the page's title, URL, and visible text as context. It connects to OpenAI GPT, Anthropic Claude, Google Gemini, or a local model through your own API key: no account, no sign-up, no tracking. It's live on addons.mozilla.org for Firefox 142 and newer, on desktop and on Firefox for Android.

Why Firefox users are underserved

Search for a ChatGPT sidebar for Firefox and, as of July 2026, most of what turns up falls into two groups. The first is thin wrappers: panels that load the ChatGPT website in a smaller window. They can't see the page you're on, so "summarize this article" means copy, paste, wait, and switch back. The second is Chrome-first assistants whose Firefox version arrives late, trails the Chrome build, or never ships at all.

Mobile is starker. Chrome for Android doesn't run extensions, so the entire Chrome-first category simply doesn't exist on phones. Firefox for Android does run extensions — making it one of the few mainstream mobile browsers where a page-aware AI assistant is possible. Few extensions take advantage of that. GlassBar does.

What GlassBar does on Firefox

GlassBar is page-aware. When you ask a question, it sends the page's title, URL, and visible text along with it — so "what does clause 4 actually mean?" or "summarize this page" works on the page in front of you, without pasting anything.

• One bar, every tab. A frosted-glass bar rests at the bottom of the page as a small pill. Hover to expand, click to pin, Esc to tuck it away.
• Keyboard first. Alt+J toggles the bar on any page.
• Streaming answers, real formatting. Headings, lists, and code render as they arrive — not raw markdown.
• Dark, light, and auto themes that persist across restarts.
• One codebase, four browsers. The same extension runs on Firefox, Chrome, Edge, and Brave — Firefox isn't a port that lags behind.

The free tier is the product, not a trial: every provider, page-aware chat, local models, themes, and the keyboard toggle, at $0 forever. A one-time $15 Pro upgrade adds Saved Chats — conversations persist per page, auto-restore when you revisit, are searchable, and export to Markdown or JSON. Never a subscription.

"Sidebar" is the search term — bar is the truth

One honest note on form factor: GlassBar is not a vertical panel that squeezes your page into a narrower column. It's a horizontal bar docked at the bottom of the tab, resting as a small pill until you need it. The page keeps its full width, the chat stays one glance away, and on a phone screen — where a vertical sidebar has no room to exist — the bottom bar is the layout that actually fits. If you searched for an AI sidebar for Firefox, this is that job, done in a different shape.

GlassBar on Firefox for Android

GlassBar is enabled for Firefox for Android on the same AMO listing. That is rarer than it sounds: most AI sidebar extensions are desktop-Chrome-only, and Chrome for Android can't run extensions at all. If you want an AI assistant that can read the page you're browsing on an Android phone, Firefox plus an Android-enabled extension is one of the few routes — and GlassBar is one of the few that takes it.

The setup is the same as desktop: install from the listing, add your API key, and ask about whatever you're reading. Everything works the way the privacy model promises — your question and the page context go straight from the browser to the provider you chose, with no server of ours in between.

ChatGPT models with your key — and everything else

To be plain about it: GlassBar is not the official ChatGPT app and is not affiliated with OpenAI. It's a bring-your-own-key extension. Paste your OpenAI API key and GPT models answer your questions about the page; the "ChatGPT experience" comes from the same models, called directly, on your own terms and your own billing.

The same bar speaks to the rest of the field: Anthropic Claude, Google Gemini, OpenRouter, xAI's Grok, Groq, DeepSeek, and any OpenAI-compatible endpoint. Each provider keeps its own key and model selection, so you can switch per task. And with Ollama or LM Studio on localhost, GlassBar runs fully offline — nothing touches the internet.

That architecture is the privacy model. No account, no backend, no proxy, no telemetry. Your key lives in the browser's local extension storage and is sent only to the provider you pick. There's no server in the middle to log, sell, or leak anything — details in the privacy policy. If you're weighing GlassBar against the account-based sidebars, the comparison table lays it out feature by feature.

How to install on Firefox

1. Open the GlassBar listing on addons.mozilla.org.
2. Click Add to Firefox. You'll need Firefox 142 or newer.
3. Open the bar's settings, pick a provider, and paste your API key.
4. Press Alt+J — or hover the pill at the bottom of any page — and ask.

On Android, install from the same listing through the add-ons manager in Firefox for Android. On Chrome, Edge, or Brave, the extension runs from the same codebase; the Chrome Web Store listing is coming soon, and Chromium users can sideload the dev build today.

Frequently asked questions