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Is Sider safe? Is Monica safe? What the two biggest AI sidebars collect

Sider and Monica put ChatGPT, Claude, Gemini and more in a sidebar on every web page. They’re hugely popular and highly rated. They also see a lot of what you do. Here is what their own store listings disclose, who is behind them, and how they compare with the AI companies’ own extensions.

By Chris · Updated Oct 3, 2026 · Facts checked Oct 2, 2026

Short answer

Both are legitimate, top-rated products, not known malware. But both can see the pages you use them on, both disclose collecting personal data, and a June 2026 report described a serious flaw in Sider. Fine for reading articles and drafting; keep them off your email, banking and work systems — or use the AI company’s own extension instead.

Sider and Monica side by side

	Sider	Monica
Chrome rating	4.9★ (about 114,500 ratings)	4.9★ (about 32,300 ratings)
Chrome users	5,000,000	3,000,000
Badge	Featured	Featured
Publisher	Vidline Inc., Boston, USA	Butterfly Effect Pte. Ltd., Singapore (maker of Manus)
Store page says it collects	Personally identifiable information, website content	Personally identifiable information, financial and payment information, personal communications, user activity
Site access	Can run on the pages you visit	Requests access to all sites reported
Security reports	“Spyder” flaw reported June 2026; fix status unconfirmed	None found in our search

From each extension’s Chrome Web Store page, read on Oct 3, 2026. Ratings and user counts change daily.

Sider

Sider is one of the most popular AI extensions in the Chrome Web Store, with a near-perfect rating from more than 100,000 reviews and Google’s Featured badge. Its listing names Vidline Inc. in Boston as the developer and discloses that it collects personally identifiable information and website content — which is expected for a tool that reads the page you’re on.

On June 10, 2026 the security firm Forever Security published research it called “Spyder”: a weakness in how Sider’s page scripts accepted messages, which it said could let a malicious website open hidden tabs, take screenshots and act inside your logged-in Gmail, Calendar, ChatGPT or Claude sessions. The report said the company hadn’t responded and no fix existed at publication. Sider has released many versions since; we couldn’t confirm whether this one is fixed. The same report described a similar flaw in another extension, MaxAI.

Monica

Monica offers the same “every AI model in one sidebar” idea, plus an agent mode. Its publisher, Butterfly Effect, also makes the Manus AI agent. Meta announced a deal to buy the company in December 2025, but China’s economic planning agency blocked it in April 2026, so Monica is not owned by Meta.

Monica’s store disclosure is broader than Sider’s: personal information, financial and payment information, personal communications and user activity. That doesn’t mean misuse — it may cover paid subscriptions and the content you ask it to process — but it’s a lot of access to grant.

Why “all-in-one” sidebars deserve extra thought

A middleman sees your text. When you use ChatGPT through Sider or Monica, your prompt goes to their servers first, then to the AI company. You’re trusting two privacy policies, not one.
They run on many pages. A sidebar that can read any page can, in principle, read your email or bank page if you open it there.
Updates are automatic. Other popular extensions changed behavior after an update — see our incident list.

Safer ways to get the same thing

Gemini in Chrome — built into Chrome and free; no extra company in the middle.
The ChatGPT extension or Claude in Chrome (paid Claude plans) — from the AI companies themselves.
The assistant’s own website in a separate tab — the simplest and most private option.
If you keep Sider or Monica, set its site access to “On click” in Chrome’s extension settings, so it only runs when you ask.

Sources: Chrome Web Store listings for Sider and Monica · Forever Security: Spyder and MaXSS · CNBC on the Meta–Manus deal · TechCrunch on China blocking the deal · Chrome Web Store: Featured badge

Quick answers

Is the Sider AI extension safe?

Sider is a legitimate, highly rated extension (4.9 stars from about 114,500 ratings, 5 million Chrome users, Featured badge) made by Vidline Inc. of Boston. Its store page says it collects personally identifiable information and website content. In June 2026 researchers reported a flaw that could let a malicious website act through it and said the company hadn’t responded; we couldn’t confirm whether it has since been fixed. Avoid using it on sensitive sites.

Is Monica AI safe?

Monica is a legitimate, highly rated extension (4.9 stars from about 32,300 ratings, 3 million users, Featured badge) made by Butterfly Effect Pte. Ltd. in Singapore, the company behind the Manus agent. Its store page says it collects personal information, financial and payment information, personal communications and user activity. Treat it as able to see what you do in the browser.

Is Monica owned by Meta?

No. Meta announced a deal to buy Butterfly Effect in December 2025, but China’s economic planning agency blocked it in April 2026, according to TechCrunch.

What is the Sider AI extension?

A browser sidebar that lets you chat with several AI models, summarize pages and videos, translate, and write on any website. It has free and paid plans.

What is safer than Sider or Monica?

The AI companies’ own options: Gemini in Chrome (built in), the ChatGPT extension, Claude in Chrome on paid plans, or simply the assistant’s own website in a separate tab. They don’t pass your text through an extra company.

Keep learning

Safety guide