If the suspicious text is in a Gmail thread, a LinkedIn post, an X reply, a ChatGPT transcript, or a Substack you are about to forward, the detector has to live in the browser, not in a separate tab. The TextSight extension opens as a Chrome side panel beside the page. Click Scan page to check everything you are reading, or highlight a passage and click Check selection to check just that part. The 0–100 score comes back in a ring, the sentences that read as AI are listed under it, and those same sentences are underlined on the page itself so you can see where they sit. The panel is the surface; the engine and the score are the ones that power app.textsight.ai.
A web detector is fine for one paste. It stops being fine when you are cycling through Gmail, LinkedIn, ChatGPT, and a Substack tab a hundred times a day and dropping the check most of the time.
The friction in a paste-and-scan detector is not the scan itself. It is the tab switch, the manual copy, the visual reorientation to a different app, the paste, the wait, and the trip back. The extension removes those steps. Select a paragraph in a Gmail message, click the toolbar icon, and the score appears in the side panel beside the page — the message stays on screen the whole time. The flow is the same whether you are reviewing a cold pitch, a LinkedIn comment, or a ChatGPT response you are about to copy into a brief.
Readers who scan suspicious text across an afternoon care less about model quality (every detector is converging there) and more about how cheap each scan is to invoke. The extension makes a single detection a three-second action: select, click, read. Over a 50-scan session of cold outreach triage or social feed review, that is meaningful time saved versus bouncing into a separate tab each time. Cheaper scans means more scans, which means catching the things you would otherwise ship.
The extension is not a separate product. It uses your existing TextSight account, the same daily scan quota, the same Humanization Score logic, and the same detector endpoint as the web app. Sign in once, the extension stays signed in, and your usage from the toolbar counts against the same daily bucket as a paste-flow scan. No second subscription, no extension-only credits, no quota fragmentation between surfaces.
The panel reads text two ways, and there is a short list of pages no extension is allowed to touch. Honest list, both columns.
Check selection. Highlight a paragraph anywhere — a Gmail message, a LinkedIn post, an X reply, a ChatGPT transcript, a comment thread, a CRM note, a reader-mode article — and the button in the panel reads Check selection · 84 words, so you can see exactly how much is about to be sent before you send it. Right-clicking the selection and choosing Check with TextSight does the same thing.
Scan page. Nothing selected, or you want the whole article rather than one paragraph: one click reads the page's own text instead, up to 25,000 characters. Your plan's per-scan limit still applies on top of that — 13,500 characters on Free.
Text boxes and editors, not just things you are reading. The panel reads standard text boxes and contenteditable editors as well as ordinary page text, so a draft you are part-way through scores the same way as something somebody sent you. Password fields and payment fields are excluded in code and are never read.
The flagged sentences get marked on the page. After a scan, the sentences that read as AI are underlined where they sit, and the panel says how many it marked. A long article does not turn into a list of fragments you then have to go and find.
Chrome's own pages. chrome:// settings, the new-tab page and the Chrome Web Store itself are closed to every extension, TextSight included. The panel says so plainly rather than returning an empty result.
PDFs. Chrome's built-in PDF viewer does not hand text to extensions, so a PDF has to go through the web app rather than the panel.
Files opened from your own disk. A file:// page needs Allow access to file URLs switched on for TextSight in chrome://extensions first. Until you do, the panel tells you that is what is missing.
No extension-only tier, no extension-only credits. Your TextSight account quota applies. Yearly billing saves 25% on every paid tier.
Billed $89.88/year — Save $30
Billed $179.88/year — Save $60
Billed $359.88/year — Save $120
Yearly billing saves 25%. View full pricing →
A standard Chrome extension install. About 30 seconds end to end. No build flags, no developer mode, no unpacked-extension warnings.
Open TextSight: AI Detector & Humanizer on the Chrome Web Store and click Add to Chrome. Chrome shows its permission prompt first. TextSight's content script is declared on all sites, so the prompt is the broad one — read and change your data on the sites you visit. What the code does with it is narrower: it listens, it remembers what you currently have selected, and it sends nothing anywhere until you click a button in the panel. Confirm and the extension installs in a few seconds. Same install flow on Edge, Brave, Arc, Vivaldi, and Opera since they all share the Chromium extension API.
Click the puzzle-piece icon in the Chrome toolbar to open the extension menu. Find TextSight in the list and click the pin icon next to it. Pinning keeps the extension icon visible in the toolbar so you can click it without opening the puzzle-piece menu every time. Most users want this on; the extension still works unpinned but the trigger is one extra click each scan.
Click the TextSight icon and sign in with the same email you use on app.textsight.ai. The extension stores an authentication token locally and stays signed in until you sign out manually or the token expires (typically 30 days). One sign-in per browser profile covers every site you use the extension on. Free, Starter, Pro, and Business accounts all carry over automatically; there is no separate extension account. You can also skip this step — the login screen offers Try 3 free scans without an account.
Open Gmail, LinkedIn, ChatGPT, Substack, an X thread, or any reader-mode article and click the TextSight icon. The side panel opens beside the page rather than on top of it, so the thing you are checking stays visible. The extension does not act on its own: it only ever sees text you hand it by clicking a button in the panel or using the right-click menu.
Click Scan page for the whole thing, or highlight a passage first and click Check selection. There is no mode to choose and nothing to configure. The 0–100 score comes back in a ring with its verdict, the flagged sentences are listed under it with their own AI percentages, and the same sentences are underlined on the page.
There is no mode toggle and nothing to configure. Every scan returns the same four things.
A 0–100 number. The panel labels it the Authenticity score; it is the same figure the web app calls the Humanization Score, computed by the same engine. Under 40 reads as likely AI, 40 to 69 as mixed, 70 and above as likely human, and the line under the ring spells it out rather than making you interpret a colour: Likely AI · 69%.
Underneath the ring, each flagged sentence with its own AI percentage. Two show by default and the rest open on a click, so a heavily flagged article does not bury the score. The same sentences are underlined on the page you scanned, and the panel tells you how many it marked there.
Every flagged sentence carries its own Rewrite button, and there is a Rewrite all underneath for the whole set. Rewriting only the flagged sentences is deliberate rather than lazy: sending the entire passage would spend your rewriter allowance on sentences that already read as human.
Recent scans stay in the panel with their score and opening words. Going back to something you checked ten minutes ago costs nothing — it does not spend another scan from your daily count.
Browser extensions with broad permissions are a real category of risk. This is the honest list of what TextSight requests, what it uses, and what it ignores.
The extension does not read pages passively. It does not scan email bodies, social feeds, chat history, or form fields in the background. The only text that ever leaves your browser is text you handed it by clicking Scan page, Check selection, or the right-click item. Close the panel without clicking either and nothing leaves the device. Password fields and payment fields are excluded in the code itself and are never read, whatever is selected. No keylogging, no clipboard monitoring, no DOM polling between scans.
The extension does not inject tracking pixels, third-party analytics scripts, or fingerprinting code into sites you visit. The only outbound network call the extension makes is to the TextSight detector endpoint on api.textsight.ai when you trigger a scan. That call carries the text you submitted and your authentication token; nothing else. No URL logging, no browsing history, no per-site telemetry.
The extension is governed by the privacy policy at www.textsight.ai/privacy.html. Text submitted through the extension is processed for the scan, counted against your daily quota, and not retained beyond the standard logging window applied to web app submissions. Sign-out clears the authentication token and the preferences cached on your machine. Manifest V3 architecture keeps the permission surface minimum-grade.
The main detector landing page covering every source model and the full Humanization Score system.
Open the overview →Sister extension for one-click humanize on selected text in Gmail, LinkedIn, ChatGPT, and most editors.
See the humanizer extension →Android app and iOS web fallback for scanning on a phone, same backend as the extension.
Open mobile guide →Full tier breakdown for Free, Starter, Pro, and Business. Annual billing saves 25%.
See pricing →Same detector and the same 0–100 score as the web app, in a side panel beside whatever you are reading. Scan the page, or check one selection, inside Gmail, LinkedIn, ChatGPT, X, Substack and most of the web. Three free scans a day without an account. Install in 30 seconds.
How TextSight works for other regions and setups.