AI assistant that highlights and summarizes the web.
Productivity
Liner AI is the browser-first research assistant that started life in 2016 as a web highlighter — think Kindle-style highlights, but for any web page you visit — and has spent the last few years rebuilding itself into something meaningfully more ambitious: a full-featured AI research assistant that lives inside your browser, reads the pages you read, cites what it finds, and increasingly competes with Perplexity in the search-with-citations lane.
The one-line positioning: Liner AI is the research assistant for people who do their reading on the web and want an AI that stays alongside them there. Its distinctive value is proximity to the browser workflow. Where Perplexity is a destination — a URL you visit to ask a question — Liner is an overlay that shows up on top of whatever page you already have open. Highlight a passage, ask a question about it, get an AI answer that draws on both the current page and the wider web. It is a different posture than any of the standalone chatbots.
Liner's user base is unusual for an AI tool — heavily international (huge in South Korea and Japan, growing in Southeast Asia and Latin America), heavily student-and-researcher-skewed, and heavily mobile-friendly in a category that has been aggressively desktop-first. That international and mobile heritage shows in the product. The mobile app is genuinely good. The multi-language support is real, not translated marketing. And the search UI feels tuned for someone reading academic papers and news articles rather than someone drafting product copy.
In 2026 Liner is a legitimate Perplexity alternative for a specific kind of user: the browser-native researcher who lives in tabs, highlights compulsively, and wants their AI attached to the reading rather than in a separate window. It is not a general-purpose ChatGPT competitor. It is not a workspace tool. It is a research overlay, and if that matches what you actually do all day, it is one of the sharpest tools in that lane.
Liner AI's feature set has expanded significantly since the pure-highlighter days, and the current tool has three overlapping surfaces: the browser extension, the mobile app, and the web app / search interface.
AI-powered web search with citations. The Perplexity-style feature. Ask a question, get a synthesized answer with source citations linked back to the original web pages. Comparable in quality to Perplexity on most queries and stronger on non-English queries in Liner's core markets.
Highlight-then-ask. Select text on any web page (via the browser extension) and ask a question about the highlighted passage. The AI answers with the context of the surrounding page, not just the highlighted words. This is Liner's original DNA showing through — the tool assumes you are reading, and layers the AI on top.
Ask-anything sidebar. A collapsible sidebar in the browser that runs an AI assistant with awareness of the current page. Ask general questions, ask page-specific questions, translate the page, summarize the page — all without leaving the article you were reading.
Highlight library. Every highlight you make across the web is saved in a searchable library with the source URL, date, and any notes you added. This is what makes Liner more than a chat tool — over time, the library becomes a personal knowledge base of what you have actually read.
PDF and document support. Upload PDFs or open them in the browser and Liner behaves the same way — highlight, ask, save. Not as feature-rich as a dedicated tool like Humata for multi-document research, but sufficient for solo reading workflows.
Multi-language support. Handles queries and answers in over 100 languages with meaningful quality on the top ten or so. Particularly strong for Korean, Japanese, Chinese, Spanish, and Portuguese — better than Perplexity in our informal testing on Korean and Japanese specifically.
Academic and news source weighting. Liner's search leans toward academic papers, news outlets, and reference sources by default, with less weight on Reddit-style social content. This makes it noticeably better for research and worse for "how do I fix X" tech-support queries.
Mobile apps for iOS and Android. Actual mobile-first apps, not just responsive web. The reading and highlighting experience on mobile is unusually strong.
Copilot for browsing. A newer feature that watches your browsing session and offers proactive summaries, related sources, and follow-up questions as you read. Some users love this; others find it intrusive. Toggleable.
Chrome and Edge extensions. The browser extension is the primary interface for most Liner users. Firefox support exists but lags on new features.
Export to Notion and other tools. Push highlights and summaries to Notion AI, Google Docs, or plain markdown. Useful for turning a research session into a starting document.
Liner's pricing has shifted over 2024-2026 into a two-tier structure that mirrors most consumer AI tools, with a genuinely useful free tier and a Pro tier that unlocks the frontier-model features.
| Plan | Price (annual) | Price (monthly) | What you get |
|---|---|---|---|
| Free | $0 | $0 | Basic AI search, limited highlights, basic browser extension |
| Pro | $10.83/month | $19.99/month | Frontier models, unlimited highlights, advanced features, mobile pro |
| Team | $19.99/user/month | $29.99/user/month | Shared highlights, team libraries, admin controls |
Free is a real tool for occasional use — you can highlight, save, and ask basic questions without ever hitting a hard cap that blocks the workflow. The AI on the free tier uses a less capable model than Pro, and search results are more limited, but the overall feel is closer to "you can live here" than to a five-minute demo.
Pro at $10.83/month annual is priced against Perplexity Pro ($20/month) as a clear alternative. This is the tier where the frontier models unlock, the highlight and search limits go away, and the Copilot-for-browsing feature becomes available. For a serious research user, this is the tier that earns the tool a place in the workflow.
Team at $19.99/user/month is a newer offering aimed at research groups and small firms. Shared highlight libraries and per-team knowledge bases are the differentiators. Not mass-market yet.
The honest read: Liner is priced meaningfully below Perplexity Pro for a comparable feature set, and the free tier is more useful than Perplexity's. For solo researchers and students in Liner's core markets — international, non-English-primary — the price-to-value ratio is genuinely strong. For US-market users who already pay for Perplexity or ChatGPT, the case for adding Liner is narrower and comes down to whether you specifically want the highlight-first browser workflow.
Pros
Cons
Students reading academic papers on the web. Highlight passages, ask questions in your native language, save to a personal library that persists across the semester. The Pro plan at $10.83/month is priced for students who use the tool weekly.
International researchers working across languages. Liner's non-English performance is meaningfully better than most Western-market competitors on Korean, Japanese, Chinese, and several other languages. If your reading is multilingual, this is one of the strongest tools.
Knowledge workers doing web-heavy research. Consultants, analysts, and content producers whose research consists of reading many web pages and building a synthesis. The highlight library plus AI Q&A workflow is genuinely productive.
Journalists working stories that require reading many sources. Highlight-and-quote workflow, plus a searchable library of past highlights, plus AI-summarized research trails.
Anyone who reads on mobile and hates having to switch to a laptop to use AI. The mobile app is the differentiator. If your reading happens on a phone commute, Liner's iOS and Android apps beat Perplexity's mobile experience.
Non-native English readers. The translate-page and ask-in-my-language features are transformative for anyone reading English content as a second language. Understated feature that changes the tool for a large user base.
Bad fit. Solo Western-market users who already pay for Perplexity — the marginal value is thinner. Teams that need enterprise collaboration — Liner Team is not there yet. Writers who need a full workspace — Liner is a reader, not a writer.
Liner's competition splits by workflow: standalone research assistants (Perplexity), browser-native readers (Readwise Reader, various highlighter tools), and general AI assistants (ChatGPT, Claude).
Perplexity — the direct search-with-citations competitor. Perplexity is stronger on general knowledge, Reddit-informed practical answers, and pure question-answering. Liner is stronger on browser-native workflow, non-English languages, and highlight-based knowledge building. For US-market users doing English research, Perplexity is often the first pick. For international researchers, Liner often wins.
Readwise Reader — the reading-and-highlighting competitor. Reader is stronger as a read-later inbox with newsletter, RSS, and Twitter integration; Liner is stronger as an AI research assistant. Some users run both.
Glasp — the social-highlighting alternative. Free, community-oriented, more focused on sharing highlights than on AI research. If the social layer matters to you, Glasp is a different animal.
ChatGPT with browser plugin — the general-purpose alternative. Handles most of Liner's job in a broader interface, though without the persistent highlight library or the on-page overlay.
Kagi Assistant — a paid search competitor that pairs a strong search engine with an AI layer. Better for users who want to leave Google entirely; different workflow from Liner's overlay approach.
Notion AI — different category, but relevant if you want your research to flow directly into a workspace. Export from Liner into Notion is a real workflow that many users adopt.
Elicit and Scholarcy — for structured academic literature review, these do more than Liner at higher prices. Liner is broader; those are narrower and deeper.
Go to Liner AI and sign up with Google or email. The onboarding is quick — the tool wants you in front of a real web page as fast as possible.
Install the Chrome or Edge extension. This is where the tool actually lives. Without the extension, you have a web app that does less than half of what makes Liner interesting.
Visit an article you actually want to read. Not a demo page. A real research paper, news article, or blog post that you were going to read anyway. Highlight a passage that seems important.
Ask a question about the highlight. Something specific — "what does this mean in practice," "what is the counter-argument," "is there evidence for this claim." The quality of the answer is what predicts whether Liner will earn a place in your workflow.
Install the mobile app. Even if you never use it, do this — Liner's mobile app is one of the reasons long-term users stay, and the library sync across devices is where the personal knowledge base starts to feel real.
Give it two weeks before evaluating the highlight library. Like any personal knowledge tool, Liner's value compounds with use. Judging on day three is unfair to the tool and to your own time.
Is Liner better than Perplexity? For general English-language question answering, Perplexity is often stronger. For non-English research, browser-native workflow, and highlight-based knowledge building, Liner is meaningfully better. The two tools do different jobs; the "which is better" question depends on what you actually do.
Which AI models does Liner use? Liner routes across frontier models — currently including GPT-4 class and Claude Sonnet class — with model selection tied to Pro tier. Model choice is not exposed to users directly.
How is Liner's non-English performance? Strong on Korean, Japanese, Chinese, Spanish, and several other languages — noticeably better than most Western-market competitors on the Asian languages specifically. This is a real differentiator for international users.
Can I export my highlights? Yes — to Notion, Google Docs, and markdown. Full library export is supported on paid plans. Data portability is a real point of trust here.
Does Liner work on PDFs? Yes, both uploaded PDFs and PDFs viewed in the browser. The workflow is comparable to a light version of Humata or ChatPDF, but Liner is not the tool if PDFs are your primary use case — a dedicated PDF tool wins there.
Is the free tier enough? For occasional research use, yes. For daily reading with AI, Pro at $10.83/month is the upgrade that unlocks the frontier models and the full feature set. For students in particular, the value at that price is strong.
Does Liner train on my highlights? Liner's stated policy is that it does not use user highlights or queries to train third-party models. For sensitive research material, read the current data policy first.
Can I use Liner offline? Limited offline support — you can view saved highlights offline in the mobile app, but AI features require a connection.
Liner AI is the right research assistant for browser-native readers, non-English-primary users, and mobile-first researchers, and the wrong tool for everyone else. It is not trying to be ChatGPT, and it is not really trying to be a workspace tool. It is trying to be the AI that lives on top of your reading, with a persistent highlight library that turns your web-browsing history into a personal knowledge base, and it does that better than most competitors.
The honest positioning depends on where you sit. For a solo researcher in Korea, Japan, or a similar market, Liner is often the sharpest tool in the category — the non-English performance and mobile experience are meaningfully ahead of Perplexity and other Western-market competitors. For a US-market solo user who already pays for Perplexity, the marginal value is thinner and comes down to whether the browser-native highlight workflow specifically matters to you. For teams, Liner is not there yet — the Team plan exists but lacks the depth of a real enterprise offering.
The pricing is a real advantage. Pro at $10.83/month annual is meaningfully below Perplexity Pro and roughly half of ChatGPT Plus for a research-focused feature set that is genuinely competitive on the axes Liner cares about. The free tier is generous enough to build a habit, and the mobile apps are good enough to keep users engaged across devices.
Start at Liner AI, install the extension, and try it on real reading for two weeks. If the highlight library and the on-page AI overlay change how you research, Liner has earned its place. If they do not, you have lost nothing but a couple of weeks of using a browser extension. In 2026, that is one of the fairest evaluation propositions in the AI tool market.