The Best Chrome Extensions for Running ChatGPT and Claude Side by Side in 2026

Here is the short answer. If you want a single Chrome extension that puts ChatGPT and Claude in one window and sends the same prompt to both, ChatHub is the most purpose-built option and the one I would try first. If you mainly want an AI panel that follows you around the web, sidebar assistants like Sider, Monica, and Merlin can show answers from multiple models, though they usually route through their own accounts rather than yours. And if you care about privacy, reliability, or you are on a company machine, the honest answer is that no extension beats two pinned browser windows and a split screen, which costs nothing and sends your conversations to nobody new.

That last option is not a cop-out. I build privacy-first tools for a living, and I compare ChatGPT and Claude constantly, for code review, for drafting, for checking each other's reasoning. I have tried the extension route and the no-extension route at length. Here is what actually holds up.

Why run two models at once

Model comparison is not a novelty. ChatGPT and Claude genuinely disagree, and the disagreements are where the value is. Claude tends to be more careful with long documents and nuanced instructions. ChatGPT tends to be faster to a workable draft and stronger on certain tool integrations. When one model confidently gets something wrong, the other often catches it, and asking the same question twice is the cheapest error check available to you.

The workflow you want is simple: type a prompt once, see both answers next to each other, and keep both conversation histories intact. Everything below is judged against that bar.

ChatHub: the purpose-built option

ChatHub is the extension people usually mean when they ask this question. It exists specifically to run multiple chatbots in a split view inside one tab. You type a prompt once, and it fans the prompt out to the models you have enabled, showing the responses in parallel columns.

What I like about it: the core comparison loop is exactly right. One input box, several answers, and you can scan the differences immediately. It supports arranging more than two models at once if you want a wider comparison, and it keeps the interaction inside a single tab, which is tidier than juggling windows.

What to check before you commit: how it connects to each model. Tools in this category generally work in one of two ways. Either they use your own API keys, which means pay-per-use billing against your developer account, or they route through the tool's own backend and subscription. Neither is wrong, but they have different cost and privacy profiles, and the details change often enough that you should read the current setup screen rather than trust any blog post, including this one. If you already pay for ChatGPT Plus and Claude Pro, understand that an extension may not be able to use those subscriptions directly, because the web subscriptions and the APIs are separate products.

Sidebar assistants: Sider, Monica, Merlin, and friends

The second category is the all-in-one AI sidebar. Sider, Monica, Merlin, and MaxAI are the established names. These add a panel to every page you visit, and most of them let you pick between models, sometimes showing more than one response at a time.

Be clear-eyed about what these are. They are not a window into your ChatGPT and Claude accounts. They are products with their own backends, their own credit systems, and their own subscriptions, which happen to offer multiple underlying models. That has real upsides: one login, one bill, page-context features like summarizing the article you are reading. It also has real downsides: your prompts flow through a third party you did not previously have a relationship with, the model versions on offer may lag or be labeled vaguely, and the free tiers are usually metered to push you toward a subscription.

If your goal is serious side-by-side comparison of the actual current ChatGPT and Claude experiences, sidebars are the weaker choice. If your goal is convenient AI assistance everywhere with occasional model switching, they are fine, provided you are comfortable with the data flow.

The no-extension setup that often wins

Here is what I actually run most days: chat.openai.com in one window, claude.ai in another, tiled half and half. On macOS, drag each window to a screen edge or use the built-in window tiling. On Windows, Snap does it in two keystrokes. Some browsers now offer split-tab views natively, and if yours does, that works too.

The advantages are boring and decisive. You get the real first-party interfaces, with every current feature, the moment each company ships it. Your conversations go only to OpenAI and Anthropic, the two parties you already accepted. Nothing breaks when either company redesigns their site, which is the chronic failure mode of extensions that wrap these interfaces. And your existing Plus or Pro subscriptions just work.

The one thing you lose is single-prompt broadcast. My fix is low-tech: write the prompt in a scratch note, then paste it into both. Two extra keystrokes. For prompts worth comparing, that cost is nothing, and it forces a second look at the prompt itself, which usually improves it.

Read the permissions before you install anything

This is the part most roundups skip. An extension that operates on chatgpt.com and claude.ai can, by construction, read what you type there. Many AI extensions request access to every site you visit, because their features require it. That is an enormous grant for a productivity tool, and your AI conversations are some of the most sensitive text you produce: half-formed ideas, private code, client details.

My rules, and I follow them myself:

• Prefer tools that request access to specific sites over tools that request access to all sites.
• Prefer open source extensions where you can at least inspect what leaves your machine.
• Never paste anything into a third-party AI wrapper that you would not paste into a stranger's web form, because functionally that is what it is.
• On a work machine, use the split-window setup and skip extensions entirely.

Also worth knowing: extensions that automate or scrape the ChatGPT or Claude web interfaces, rather than using official APIs, sit in murky territory with both companies' terms of service, and they break whenever the underlying sites change. API-based tools are more stable and more legitimate, at the cost of separate usage billing.

My recommendation

For most readers: start with the split-window setup today. It is free, private, and unbreakable. If you find yourself pasting the same prompt into both models many times a day, install ChatHub, check how it authenticates to each model, and decide whether the convenience is worth the cost and the data flow. Reach for a sidebar assistant only if what you really want is ambient AI help on every page, not rigorous model comparison.

FAQ

Can one extension use my existing ChatGPT Plus and Claude Pro subscriptions? Generally no. The consumer subscriptions cover the official apps and websites. Third-party tools typically use the APIs, which are billed separately, or their own backend subscriptions. Check the specific tool's current documentation, because arrangements change.

Is it against the rules to use these extensions? Tools that use the official APIs with your keys are legitimate. Tools that automate the web interfaces may conflict with terms of service and tend to break often. When in doubt, prefer API-based tools or the plain websites.

Which model should I trust when they disagree? Neither, automatically. A disagreement is a signal to verify, not a tiebreaker to outsource. In my experience the disagreement itself is the product: it tells you exactly where to look closer.

Do these extensions slow the browser down? Sidebar assistants that inject into every page add some overhead everywhere. A dedicated comparison tab like ChatHub only costs you when it is open. The split-window approach costs nothing beyond the two sites themselves.

What about Firefox or Safari? The split-window approach works identically everywhere. Extension availability varies by browser, so check each tool's listing for your browser before assuming parity with Chrome.