Model
Claude in any tab: a browser sidebar for Claude models
Copilotly runs Anthropic's Claude models in a sidebar beside the page you are reading, in Chrome, Edge, Firefox, Brave and Opera. It is not made by Anthropic; it is a separate assistant that offers Claude next to GPT, Gemini and others.
By the Copilotly editorial team. Last verified November 11, 2026 against the current Copilotly release.
Quick answer
To use Claude in Firefox, Opera, Edge or Chrome, install the Copilotly extension, choose Claude Sonnet 5.5, Opus 5.5 or Fable 5.1 in the model menu and press Alt+C. The free plan covers Claude Haiku 5.5 plus 10 premium messages a day. Safari has no build yet. Copilotly is independent of Anthropic.
- Claude Sonnet 5.5, Claude Opus 5.5 and Claude Fable 5.1 in the model menu
- Works in Firefox and Opera as well as Chrome and Edge
- Free plan includes 10 premium-model messages a day
- Or use your own Anthropic API key, unmetered by Copilotly
At a glance
- Claude models
- Sonnet 5.5, Opus 5.5, Fable 5.1, Haiku 5.5
- Price to start
- Free, no card; 10 premium messages a day
- Works in
- Chrome, Edge, Firefox, Brave, Opera, Arc, Vivaldi
- Safari
- Not supported yet
- Your own key
- Anthropic API key, never metered by Copilotly
- Made by
- Copilotly, not Anthropic
How to use Claude in any tab
Install the extension
Add Copilotly from the download page for Chrome, Edge, Firefox, Brave, Opera, Arc or Vivaldi. Create a free account when it asks; there is no card.
Pick a Claude model in the model menu
Open the model menu and choose Claude Sonnet 5.5 for everyday writing and reasoning. On Pro, Claude Opus 5.5 and Claude Fable 5.1 are the frontier options. Claude Haiku 5.5 is the fast model.
Open it on any page with Alt+C
Press Alt+C to open the sidebar beside whatever page you are on. Ask about the page, select text and rewrite it, or start a new chat. Switching to another model mid-conversation is one click in the same menu.
What does Claude in a browser sidebar do?
Choose a Claude model and the sidebar answers with Claude while it can see the tab you have open. Ask for a summary of a long article, a critique of the draft in front of you, or an explanation of a dense passage.
Writing and editing in place
Claude is often picked for natural-sounding writing, and Copilotly's picker describes Claude Sonnet 5.5 as natural writing with careful reasoning. The rewrite-anywhere toolbar lets you use it on text you select in Gmail, Google Docs, LinkedIn or any text box, with tone and length pickers, a word-level diff and undo.
Documents and research
The same chat handles PDF, Word, Excel and CSV files, web search with citations and deep research. Page translation, YouTube summaries and image generation work whichever model you pick.
Switching models mid-conversation
Because every model shares the menu, you can ask GPT or Gemini the same question when you want a second opinion, without leaving the page.
Is there an official Claude browser extension, and does it work in Firefox?
Anthropic does publish one, called Claude in Chrome. as of November 2026, Anthropic's help article says to install it from the Chrome Web Store and states that it is not supported on other Chromium-based browsers or on mobile. We found no Firefox or Safari version. Which Claude plans include it has changed over time, so check Anthropic's pricing page before you plan around it.
When Anthropic's own apps are the better choice
If Claude is the only assistant you use, want Anthropic's features as they ship, or want conversations kept in your Anthropic account, use Anthropic's apps. See Anthropic's Claude page for what they cover now.
Where Copilotly differs
- Claude in Firefox, Edge, Opera and Brave. One extension, not tied to Chrome alone. Firefox and Edge have their own listings; Opera and Brave install the Chrome Web Store build.
- Claude beside other models. GPT, Gemini, Grok, DeepSeek and Mistral are in the same sidebar.
- Bring your own key. Use your Anthropic API key and pay Anthropic directly.
- Editing in place. Rewrite, translate and summarise where the text already is.
The Copilotly vs Claude comparison is the detailed version, and the ChatGPT vs Claude vs Gemini for professional work guide compares the models themselves.
Which Claude models do you get on each plan?
The tier decides your limit. The descriptions below are the one-line descriptions in Copilotly's model picker; for current specifications such as context window and pricing, see Anthropic's model overview.
| Model | Tier | Free plan | Pro plan |
|---|---|---|---|
| Claude Haiku 5.5 | fast | Included, within your token allowance | Included, within your token allowance |
| Claude Sonnet 5.5 | premium | 10 messages a day, then Claude Haiku 5.5 | Unlimited |
| Claude Opus 5.5 | frontier | Your own API key only | 30 a day, then Claude Sonnet 5.5 |
| Claude Fable 5.1 | frontier | Your own API key only | 30 a day, then Claude Sonnet 5.5 |
Claude Sonnet 5.5
Natural writing, careful reasoning. It is the model to start with, and Free includes 10 messages a day on it.
Claude Opus 5.5
Described in the picker as Anthropic's flagship for complex work. Pro gets 30 frontier-model messages a day, then the chat steps down to Sonnet 5.5.
Claude Fable 5.1
Described as Anthropic's most capable model. It is also a frontier model: the same Pro limit of 30 frontier messages a day applies, and it steps down to Sonnet 5.5 after that.
Claude Haiku 5.5
Quick and thoughtful. It is the fast model on every plan within your token allowance.
Pro is $6.99/week, $19.99/month or $149.99/year, with a 7-day free trial for first-time subscribers. See pricing for the full limits.
Can I use Claude without a subscription?
On the free plan
Yes, with no card. The free plan includes Claude Haiku 5.5 and 10 premium-model messages a day, which is enough to judge Claude Sonnet 5.5 on your own work. When the premium messages run out, the chat continues on Haiku 5.5.
On your own Anthropic API key
Every model on this page can also run on your own API key. Requests made on your own key are never metered by Copilotly, whatever the model's tier, and that includes frontier models on the free plan, which are otherwise Pro-only. You pay the provider directly at their API rates. The steps are on the bring your own key page.
With an Anthropic API key you can use Claude Opus 5.5 and Claude Fable 5.1 on the free plan too, at Anthropic's rates. API billing is separate from any Claude subscription you may have with Anthropic, so a Claude chat plan does not by itself give you an API key.
When should I pick Sonnet, Opus, Fable or Haiku?
Default choice
Use Claude Sonnet 5.5 for most work: drafting, editing, explaining a page, reasoning through a decision. It is also the cheapest way to try Claude on Free, because you get 10 messages a day without a key.
Hard problems
Save Opus 5.5 and Fable 5.1 for the work where extra capability earns one of your 30 daily frontier messages: a long analysis, a complex draft, a careful review of a contract you will then take to a professional. Do not treat the output as advice. Read it, and check the details that matter.
Speed
Claude Haiku 5.5 is quicker for small edits, definitions and lookups.
Second opinion
Switch to GPT in the same chat when a result looks off. No model is right every time. The AI employment contract review guide is a worked example of using an AI assistant on a contract; treat any result as a first read, not legal advice.
How does Claude compare with the other models in the picker?
The table lists one model from each provider. The Claude row comes from Copilotly's model catalogue; Anthropic's model overview is the authority on its current specifications.
| Model | Context window | Image input | Source (Nov 2026) |
|---|---|---|---|
| GPT-6.1 Terra | 1.05M | Yes | OpenAI docs |
| Claude Sonnet 5.5 | 1M | Yes | Copilotly catalogue |
| Gemini 4 Argon | 1M | Yes, plus audio, video and PDF | Google AI Studio docs |
| DeepSeek V4 Pro | 1M | No (Flash: yes) | DeepSeek docs |
| Grok 4.7 | 500K | Yes | xAI docs |
| Mistral Large 4 | 1M | Multimodal | Mistral docs |
Reading the comparison
Context window and image input tell you what fits, not how well a model handles it. Writing style is where people most often say they can feel a difference between models, and it is the hardest thing to put in a table. Try the same paragraph on Claude Sonnet 5.5 and one other model with the rewrite toolbar's diff view on.
Where another model may suit you better
If you need audio or video input, Google lists those for Gemini 4 Argon. If you need the cheapest reasoning model on your own key, look at DeepSeek. If you work mainly in Chrome and want a first-party extension, Anthropic's own may fit.
How do I get better answers from Claude in the sidebar?
Select text first when editing
For rewrites, select the passage and use the toolbar instead of describing it in chat. You get a diff against your original, versions, and undo, which makes it easy to keep what you like.
Ask for a critique before a rewrite
A useful sequence with a long draft is to ask Claude what is unclear or unsupported, fix those parts yourself, then ask for a tighter version. You keep the judgement, and it does the line editing.
Attach the file, then ask for page references
With chat with PDF, ask where in the document each claim comes from so you can check it. Do the same with web search: ask for sources and open them.
Keep frontier models for the hard part
Draft and explore on Sonnet 5.5 or Haiku 5.5, then bring the final difficult question to Opus 5.5 or Fable 5.1. That spends your 30 daily frontier messages where they matter.
Does Claude work in Firefox, Opera and Safari?
This is the question most people searching for Claude in Firefox, Claude in Opera or Claude in Safari want answered plainly. Through Copilotly: yes for Firefox, Opera, Brave, Edge and Chrome; not yet for Safari.
| Where | Status | How |
|---|---|---|
| Chrome | Supported | Chrome Web Store |
| Edge | Supported | Its own Edge Add-ons listing |
| Firefox | Supported | Its own Firefox Add-ons listing |
| Brave | Supported | Installs the Chrome Web Store build |
| Opera | Supported | Installs the Chrome Web Store build |
| Arc, Vivaldi | Supported | Install the Chrome Web Store build |
| Safari | Not yet | There is no Safari build in the App Store |
| iPhone, Android | Supported | The Copilotly iOS and Android apps, which work on the free plan |
On iPhone, use the Copilotly iOS app, which works on the free plan.
Who it is for
Professionals editing their own writing
Select a paragraph in a document or email, open the rewrite toolbar and pick Claude Sonnet 5.5. Choose a tone and a length, then read the word-level diff to see exactly what changed. Undo any change you dislike. Because the edit happens in the text box, you do not paste between tabs, and you stay in charge of what is sent.
Researchers working through long PDFs
Open a PDF and use chat with PDF with Claude selected. Ask for the method, the main claim and its limits, then ask where each answer appears in the paper. Treat the summary as a map, and read the sections you will rely on yourself.
Firefox and Opera users who want Claude beside the page
Anthropic's own extension is Chrome only, according to its help article, so a Firefox or Opera user has no first-party sidebar. Install Copilotly from Firefox Add-ons or the Chrome Web Store build in Opera, pick Claude, and press Alt+C.
Developers and teams with an Anthropic API key
Connect the key under bring your own key and use Opus 5.5 or Fable 5.1 on the free plan without Copilotly metering. Anthropic bills usage at its API rates, so watch your own usage dashboard.
Claude through Anthropic's apps or through Copilotly
| Anthropic's Claude apps and extension | Claude in Copilotly | |
|---|---|---|
| Models | Anthropic's models | Claude plus GPT, Gemini, Grok, DeepSeek, Mistral |
| Browser extension | Claude in Chrome, Chrome only per Anthropic's help article (as of Nov 2026) | Chrome, Edge, Firefox, Brave, Opera, Arc, Vivaldi |
| Firefox and Opera | Not supported (per the same article) | Yes (Opera via the Chrome Web Store build) |
| Rewrite selected text on any site | Not its main purpose | Yes, with diff and undo |
| Your own API key | Not how it is used | Yes, unmetered by Copilotly |
| Newest Anthropic features first | Usually | Only what Copilotly has built in |
| Free to try | Check Anthropic's plans | Free plan, 10 premium messages a day |
If something goes wrong
Claude Opus 5.5 or Fable 5.1 will not run on the free plan
They are frontier models, which need Pro or your own Anthropic API key. Start the Pro trial or connect a key. Claude Sonnet 5.5 is available on Free within 10 messages a day.
The chat changed to Claude Haiku 5.5 on its own
That is the fallback after you use your 10 daily premium messages on Free. On Pro, frontier models fall back to Sonnet 5.5 after 30 a day. Counts reset daily. Requests on your own key are never metered.
I cannot find Claude in Safari
There is no Safari build of Copilotly yet, so Claude cannot run there through it. Use Chrome, Edge, Firefox, Brave or Opera on a computer, or the Copilotly iOS app on an iPhone.
Alt+C does not open the sidebar
Another extension or the browser may be using the same shortcut. In Chrome, Edge and Brave open chrome://extensions/shortcuts (Edge uses edge://extensions/shortcuts) and check what is assigned to Copilotly. In Firefox, open the Add-ons page, use the gear menu and choose Manage Extension Shortcuts.
Guides that go with this
ChatGPT vs Claude vs Gemini: We Tested Real Legal, Medical, and Tax Questions
We put ChatGPT, Claude, and Gemini through dozens of real professional questions covering contract review, lab results, retirement planning, and tax deductions. Each platform showed clear strengths and surprising failure modes, and none of the 3 matched domain-specific copilots for high-stakes guidance.
5 Employment Contract Clauses to Negotiate Before You Accept the Offer
Nearly 40% of American workers sign restrictive covenants they do not fully understand. This clause-by-clause guide covers non-compete enforceability after the FTC rule, IP assignment language that can claim your side projects, arbitration traps, severance terms, and stock option vesting, with real negotiation success data.
Best AI Copilots by Profession (2026): Honest Picks for 8 Fields
We picked the best AI copilot for 8 professions and use cases in 2026: GitHub Copilot for developers, Microsoft 365 Copilot for office workers, and domain-specific copilots for legal, health, tax, finance, career, and small business questions. Every pick includes real alternatives, honest pricing, and the cases where a different tool wins.
Common questions
Is this Anthropic's official Claude extension?
No. Copilotly is independent and not affiliated with Anthropic. It uses Claude models through Anthropic's API. Anthropic has its own apps and a Chrome extension; if Claude is all you need, those are the direct choice.
Which Claude models can I use?
Claude Sonnet 5.5 (premium), Claude Opus 5.5 and Claude Fable 5.1 (frontier), and the fast Claude Haiku 5.5.
Can I use Claude without a subscription?
Yes. The free plan covers Claude Haiku 5.5 and 10 premium-model messages a day. A free account is needed; a card is not. With your own Anthropic API key you can also use the frontier models.
Is Claude available in Safari?
Not through Copilotly. There is no Safari build yet, so use Chrome, Edge, Firefox, Brave or Opera on a computer, or the iOS app on an iPhone.
Can I use Claude in Firefox, Opera or Safari?
Copilotly is the same extension across browsers, so Claude is too. It is listed for Firefox and Edge. Brave and Opera install the Chrome Web Store build, and Arc and Vivaldi do the same. Safari is not supported yet: there is no Safari build in the App Store, so use one of the other browsers on a Mac, or the iOS and Android apps on a phone.
Can Claude read a PDF or the page I have open?
Yes. The sidebar can use the current page as context and can chat with PDF, Word, Excel and CSV files. See chat with PDF.
Sources
Keep going
Use Claude on any page, in any browser
Install the free extension, pick a Claude model and press Alt+C. Firefox and Opera included. No card needed.