The key takeaways

  • The strongest AI Chrome extensions in late 2026 are Perplexity for cited answers, SciSpace for academic papers, and Harpa AI for research you want to automate.
  • For writing, Grammarly remains the default correctness layer, Compose AI handles inline autocomplete, and AIPRM supplies a huge community prompt library.
  • Sider and Monica are the two leading multi-model AI sidebars, and OpenAI's official ChatGPT extension gained tab-aware powers after the Atlas browser was retired.
  • Every tool here has a free tier, but daily and monthly credit caps decide how usable it is, so check the limits before you commit.
  • More than half of AI-branded extensions collect user data according to Incogni's 2026 study, so vet permissions and privacy policies before installing anything.
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9 AI Chrome Extensions That Make Research, Writing, and Browsing Easier

The best AI Chrome extensions right now are Perplexity for cited answers, SciSpace for academic papers, Harpa AI for automating research, Grammarly and Compose AI for writing, AIPRM for prompt templates, and Sider, Monica, and OpenAI’s official ChatGPT extension for browsing and summarizing. All nine have free tiers, though their usage allowances differ.

An AI Chrome extension is a small add-on for Google Chrome that connects a large language model to the page in front of you, so it can answer, draft, or summarize web pages with AI while you stay put. Instead of copying text into a chatbot tab, the extension reads what you’re reading and works where you work.

Most are front ends for the same handful of models, mainly GPT, Claude, and Gemini. The real differences are interface, workflow, and above all free-tier limits, which decide whether you can live free or hit a wall by Tuesday.

The 9 AI Chrome extensions at a glance

ExtensionCategoryFree tierPaid from
PerplexityResearch and searchUnlimited basic searches with citations, about 5 Pro searches a dayPro $20/mo or $200/yr
SciSpaceAcademic researchFree plan with limited features$12/mo billed annually ($20 monthly)
Harpa AIResearch automation10 messages a day via web sessions, 100 command runs totalEUR 14.30/mo billed annually, EUR 238 lifetime
GrammarlyWritingUnlimited corrections plus 100 AI prompts a monthPro $12/mo billed annually ($30 monthly)
Compose AIWriting1,500 words a month, 5 rephrases, 10 AI emails, 50 autocompletionsPremium plan (priced on compose.ai)
AIPRMWriting and promptsFree version with 5,400+ community prompts, usable foreverPlus $10/mo, Pro $33/mo
SiderSummarizing and sidebar30 basic credits a dayTiered plans, live prices on sider.ai
MonicaSummarizing and sidebar40 chats a dayFrom about $9.90/mo
ChatGPT (OpenAI)Browsing and assistantFree to install with a ChatGPT accountChatGPT plans sold separately

Most of these tools meter usage through a credit system, where each message or summary burns a fixed number of credits from a daily or monthly allowance. Cheaper models cost fewer credits than premium ones, so two “unlimited” plans can behave very differently. Read the fine print, not the marketing.

For research

These three cover the pipeline: finding sources, understanding papers, and automating the rest.

1. Perplexity (best for sourced answers)

Perplexity is an answer engine that replies with summaries and inline citations, not a list of blue links. The Perplexity Chrome extension brings that in-page: highlight text on any site for a sourced answer without leaving the tab, which is why HundredTabs’ 2026 ranking picks it for in-page fact-checking.

The free tier is usable: unlimited basic searches with citations and roughly five Pro searches a day, per Kripesh Adwani’s September 2026 roundup. Pro costs $20 a month or $200 a year and adds stronger models, higher Deep Research limits, and file uploads, per Perplexity’s plan guides.

Citations aren’t a guarantee. One detailed Pro review on Medium calls Perplexity “an excellent starting point and a terrible finishing point” for accuracy-critical work: sources can be miscited or thin.

Best for: students and researchers who want cited answers instead of ten open tabs.

2. SciSpace (best for academic papers)

SciSpace is an AI research tool for people who read actual papers. Its Chrome Web Store listing promises to “do hours of research in minutes”: the Lit Review tool searches more than 270 million papers and returns answers with citations, making it easier to spot a real reference versus a hallucinated one.

Where it earns its keep is PDFs. Highlight a dense formula, table, or methods paragraph for a plain-language explanation, then compare papers side by side or draft with citation support.

A free plan comes with limited features; Premium runs $12 a month billed annually or $20 month to month, per the SciSpace pricing page.

Paperguide’s May 2026 comparison finds SciSpace strong at understanding individual papers but weaker at keeping context across modules. It is not built for PRISMA-grade systematic reviews.

Best for: grad students and academics drowning in PDFs.

3. Harpa AI (best for research you want to automate)

Harpa AI handles the boring half of research: monitoring, extracting, repeating. It runs page-aware AI commands on any site, watches pages for changes, and alerts you to price drops or back-in-stock events, why reviewers call it several tools in one.

The free plan is real but thin: the demo tier gets web-session access to ChatGPT, Claude, and Gemini limited to 10 messages a day, plus up to 100 AI command runs total, per Harpa’s official pricing page. Paid plans start at EUR 14.30 a month billed annually, with a EUR 238 lifetime option, and every tier supports bring-your-own API keys so you can pay per token instead.

A hundred free command runs can disappear quickly with monitoring and automation. Heavier features require a paid plan or your own API key.

Best for: bloggers, SEOs, and deal hunters who want an AI that keeps watching pages after they close them.

For writing

A correctness layer, an autocomplete engine, and a prompt library cover most writing jobs inside Chrome.

4. Grammarly (best for correctness everywhere)

Grammarly is still the default AI writing assistant for Chrome, and Free now includes generative AI. Grammarly Free fixes spelling, grammar, and punctuation, shows your tone, and includes 100 AI prompts a month, per Grammarly’s plans page. Core corrections don’t count against that budget.

Grammarly Pro costs $12 a month billed annually or $30 month to month, per Grammarly’s support docs and ExternalSoftware’s October 2026 review, raising the allowance to 2,000 AI prompts with full-sentence rewrites, tone control, and plagiarism plus AI-text detection.

Your text is processed on Grammarly’s servers, and Incogni’s 2026 study flagged writing assistants as high-impact because they see everything you type. Free users also get constant upsell nudges, and aggressive rewrites can flatten your voice.

Best for: anyone who writes in English across lots of sites and wants corrections to just happen.

5. Compose AI (best for autocomplete while you type)

Compose AI does one thing: it autocompletes sentences as you type across your tools, with drafting and rephrasing attached. The official site describes a free plugin that learns your writing voice and claims to cut writing time by 40 percent, worth a grain of salt.

This is the pick if your bottleneck is email. Type ”//” to trigger it, accept tab-completions for full sentences, and let it draft Gmail replies. The free tier, documented in the September 2026 roundup: 1,500 words a month, 5 rephrases, 10 AI emails, and 50 autocompletions, with a premium tier adding personalization and higher limits.

Reviewers call it closer to a smarter Gmail Smart Compose than a full assistant, and the word budget is small enough that heavy writers hit it.

Best for: email-heavy people who want suggestions inline rather than in a sidebar.

6. AIPRM (best for prompt templates)

AIPRM is a prompt management layer for generative AI, known for a community library of ready-made prompts for ChatGPT, Claude, Gemini, and image tools. If your work means repeating well-crafted prompts for SEO briefs or outreach emails, it saves reinventing them weekly.

The free version is usable forever with the community library, which AIPRM’s pricing page puts at 5,400+ public prompts. Paid plans add private templates, tone and style controls, and prompt forking: Plus is $10 a month, Pro is $33. Pricing is USD only and sales are non-refundable.

A well-known r/ChatGPT thread titled “Is anyone else here also disappointed with AIPRM?” captures complaints about features drifting behind the paywall, and the 2026 AI Toolbox buyer’s guide lists a roughly 3.9 out of 5 Chrome Web Store rating. The library is still excellent; upsell pressure is real.

Best for: content and SEO teams that reuse proven prompt recipes.

For reading, summarizing, and browsing

An AI sidebar is a panel that docks beside the page you’re on, giving the model a live view of that page so you can chat about it, summarize it, or extract from it without switching tabs. This is the most crowded category: the two leaders below are near-twins from rival teams, followed by the official option from OpenAI.

7. Sider (best all-round AI sidebar)

Sider is the biggest name here, claiming over 10 million active users on its own site, though its Chrome Web Store listing shows around 5 million and Prompt Architects notes the numbers measure different things. It puts GPT, Claude, Gemini, and Grok into one sidebar for chatting, summarizing pages, PDFs, and YouTube videos, translating, and OCR.

Prompt Architects’ September 2026 review lists 30 basic credits a day on the free tier, citing Sider’s help center. It does not give exact paid-plan prices; those are available on Sider’s pricing page.

That review flags a vague refund policy, a cap of 1,500 advanced credits a month on the “Unlimited” plan, and features spread across five product areas. Tom’s Guide’s February 2026 hands-on, though, named Sider the best extension for staying in research flow.

Best for: heavy readers who want one sidebar for every model and content type.

8. Monica (best all-in-one assistant)

Monica is Sider’s closest rival and lands on nearly every 2026 best-of list. Kripesh Adwani calls it his favorite all-in-one assistant, and Tom’s Guide crowned it best for living inside your workflow without the tab-switching “context tax.”

The free plan allows 40 chats a day with limited trials of features like ChatPDF and image generation, per that roundup. Paid plans start at roughly $9.90 a month, per Slashdot’s 2026 comparison; annual billing is cheaper per Monica’s pricing page.

A security-focused review of browser AI extensions criticized Monica (and Sider) for collecting sensitive data despite their privacy promises. As with any page-reading extension, assume everything it sees could leave your device.

Best for: people who want one assistant that does a bit of everything at a lower entry price.

9. ChatGPT by OpenAI (best if you already live in ChatGPT)

The newest story in the category: OpenAI shut down its ChatGPT Atlas browser on August 9, 2026, and folded those powers into its official ChatGPT Chrome extension. Per The Verge’s October 15, 2026 report, you can now tag Chrome in the ChatGPT web or desktop app and ChatGPT will read your open tabs: comparing products, filling forms, building comparison sheets, and drafting emails from tab contents.

The extension also gained a sidebar with what OpenAI calls the full power of ChatGPT plus your conversation history, so you can ask about the current page without leaving it. It’s free to install from OpenAI’s Chrome Web Store publisher page, which also lists a separate ChatGPT Search extension; no paid plan is needed.

An extension that reads and acts on your tabs requests about as much as an extension can, and Incogni’s 2026 research ranked the related ChatGPT Search extension among the high-risk-likelihood, high-risk-impact group. Grant it deliberately.

Best for: people already using ChatGPT who want it woven into the browser they have.

Also considered

Three tools nearly made the cut. MaxAI has a generous free tier: 10,000 fast AI responses and 300 smart responses a month, per MaxAI’s pricing page. Merlin is a strong multi-model alternative Tom’s Guide liked for long summaries, and Glarity is a free, open-source summarizer for pages and YouTube.

How I narrowed down the extensions

I looked at what each extension adds to the browser, how quickly its free allowance runs out, and what access it needs to your pages. Product documentation supplied the plan details; reviews from Kripesh Adwani, HundredTabs, and Tom’s Guide helped with the comparisons. I also read Reddit discussions and Incogni’s study of more than 440 AI-branded extensions to weigh privacy concerns alongside convenience.

Sider and Monica need extra care when comparing plans: prices can vary by region, and allowances differ by model.

How to vet an AI Chrome extension in 5 steps

Before any AI extension reads your email or your research, spend five minutes on this.

  1. Check who published it. Confirm the Chrome Web Store developer name matches the official company, not a lookalike. Researchers documented 30 copycat extensions impersonating AI tools that secretly collected data from 260,000+ Chrome users in February 2026.
  2. Read the permissions list. Watch for “read and change all data on all websites” and scripting access. Incogni’s study found 42 percent of the AI extensions it analyzed use scripting permissions, and over half collect user data.
  3. Read the privacy policy for one thing: where your page text goes. Some tools process on-device; most send page content to cloud APIs. If the policy can’t answer that plainly, treat silence as your answer.
  4. Do the free-tier math. Multiply the daily credits or monthly words by your real usage. Thirty credits a day sounds fine until one PDF summary eats ten of them.
  5. Install, then contain. Set site access to “on click” instead of “on all sites,” check CPU and memory in Chrome’s Task Manager (Shift+Esc), and revisit chrome://extensions monthly.

Frequently asked questions

What are the best AI Chrome extensions right now?

For most people in late 2026: Perplexity for cited research, Grammarly for writing, and Sider or Monica as an all-purpose AI sidebar. Harpa AI is the pick for automation and page monitoring, SciSpace for academic papers, and OpenAI’s official ChatGPT extension if you’re already in that ecosystem.

Are AI Chrome extensions safe?

They can be, but the category defaults to more access than most people realize. Incogni’s 2026 study of more than 440 AI-branded extensions found over half collect user data, nearly a third gather personally identifiable information, and the analyzed tools totaled more than 115 million downloads. Vet permissions and check where your page text goes.

Do AI Chrome extensions cost money?

Every extension here is free to install and use at a basic level, but nearly all are freemium with daily or monthly credit caps. Real spending starts when you need premium models or higher limits, typically around $10 to $20 a month.

Which AI Chrome extension is best for research?

Perplexity for finding cited answers fast, SciSpace for understanding academic papers, and Harpa AI for automating repetitive research and monitoring pages. I would suggest students start with Perplexity; grad students juggling PDFs get more from SciSpace. Harpa is the only one of the three built for watching pages over time.

Is there a free ChatGPT Chrome extension?

Yes. OpenAI publishes an official ChatGPT extension on the Chrome Web Store, free to install with a ChatGPT account, and it now includes a page-aware sidebar plus tab-reading features via the ChatGPT apps. The separate ChatGPT Search extension adds ChatGPT as a Chrome search option. Paid plans aren’t required to install.

Do AI Chrome extensions slow down Chrome?

They can, because sidebars inject scripts into every page you open, but the impact varies widely by extension and setup. Use Chrome’s Task Manager (Shift+Esc) for each extension’s CPU and memory cost, and set site access to “on click” so an idle one does nothing.

Should I use an AI extension or an AI browser?

The browser question got messy in 2026: OpenAI retired its Atlas browser in August and moved those powers into its Chrome extension, while Perplexity’s Comet browser became free for everyone in October 2025. Extensions keep your logins, passwords, and habits in Chrome while adding AI where you need it, the lower-friction path for most people.

Sources

Article overview

The best AI Chrome extensions for research, writing, and summarizing in 2026, with verified free limits, pricing, and honest privacy notes for all 9 picks.