Is KeyGlow completely free?

Yes. Every feature is free with no account, no trial and no usage limit. The highlighting runs on your own device, so there are no per-request costs to pass on to you. The site is supported by display advertising.

How does automatic highlighting work?

KeyGlow splits your text into sentences, strips out common filler words and scores what remains. It uses a TextRank-style graph to find the sentences most connected to the rest of your text, TF-IDF keyword weighting to find the terms that carry meaning, and pattern matching to spot statistics, dates and definitions. Position, sentence length and discourse markers such as "in conclusion" act as supporting signals, and a redundancy filter stops two sentences that say the same thing from both being highlighted.

Do I need an account?

No. There is no sign-up, no email address and no login. Open the page, paste your text and highlight it.

Your text is never uploaded. All analysis happens inside your browser tab using JavaScript, so the words you paste are never sent to a server, an API, an analytics tool or an advertiser. Nothing is saved unless you explicitly choose to save a draft on your own device. Advertisements on the page may independently collect technical and usage data according to their own privacy policies, but they have no access to the contents of the editor.

Can I highlight long articles?

Yes, up to 50,000 characters per analysis — roughly 8,000 words, or about thirty pages. Larger inputs are processed on a background thread so the page stays responsive while it works.

Can I download my highlighted text?

Yes. You can copy the highlighted text with its colours intact, copy the key takeaways as a plain list, download a self-contained HTML file, or print a clean study-friendly version straight from your browser.

Does KeyGlow use artificial intelligence?

Not in the large language model sense. KeyGlow uses classical statistical text analysis — graph-based sentence ranking, keyword weighting and pattern detection. That is what keeps it instant, free and private. It means KeyGlow is very good at finding the sentences that carry the most information in your text, but it does not understand meaning the way a human reader does, so treat the highlights as a strong starting point rather than a final judgement.

What kinds of text work best?

Explanatory prose does best: textbook chapters, lecture notes, news articles, research summaries, reports and essays. Poetry, dialogue, song lyrics and bullet lists of single words give weaker results, because the algorithm relies on sentences sharing vocabulary with one another.

Privacy Policy

Last updated: 2026-10-13

The short version

The text you paste into KeyGlow is analysed by JavaScript running inside your own browser tab. It is never transmitted to us, never written to a server log, and never stored in a database. We do not have accounts, so we do not hold your name, email address or password. The one caveat worth reading carefully is the advertising section below, because advertisements on this site are served by a third party that sets its own cookies.

Text you paste into the highlighter

All sentence segmentation, ranking and highlighting happens on your device. The page makes no network request containing your text — not to us, not to an AI provider, not to an analytics service, and not to an advertiser. Large inputs are moved to a Web Worker, which is still a thread inside your own browser.

Nothing you paste is saved between visits. Reloading the page clears it. We do not write your text to localStorage or any other persistent storage.

What we do store on your device

Exactly one item: your light or dark theme preference, under the key keyglow-theme. It stays on your device, is never sent anywhere, and you can remove it by clearing your browser’s site data.

Advertising

This site is free to use and is funded by display advertising. Advertising is delivered by third-party ad networks, which may independently collect technical and usage information such as your IP address, device and browser type, approximate location, referring page and the advertisements you have been shown or interacted with. They may use cookies, web beacons or similar technologies to do this, including for frequency capping and personalised advertising.

This collection is governed by the ad network’s own privacy policy, not ours, and we do not receive or control the data they gather. What we can tell you is what they cannot reach: advertisement code is loaded into isolated containers rendered outside the editor, and it has no access to the contents of the text area, the highlighted output or your clipboard.

Depending on where you live, you may have the right to object to personalised advertising or withdraw consent. You can also limit this collection with your browser’s cookie controls, your operating system’s advertising identifier settings, or a content blocker. KeyGlow’s highlighting features work fully with advertising blocked.

Hosting and server logs

The site is served as static files by a hosting provider, which may keep standard access logs (IP address, timestamp, requested path, user agent) for security and abuse prevention. These logs record that a page was requested; they never contain the text you pasted, because that text is never sent in a request.

Children

KeyGlow is a general-purpose study and reading tool and is not directed at children under 13. We do not knowingly collect personal information from children.

Changes to this policy

If we change how the site handles data — for example by adding an analytics provider or a new ad network — we will update this page and the date at the top. Material changes will be reflected here before they take effect.

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