OCR It – pull text out of un-copyable documents for your LLM

thiagolima

Half the context I want to give a model is locked inside something I can't select from: a scanned book, a slide deck, a course viewer, a "PDF" that's really page images. Copy-paste gets you nothing, and screenshotting 200 pages by hand isn't a plan. OCR It is a Chrome extension for that gap. You drag out a capture region once — the text block of the reader, say. After that, one hotkey per page screenshots that exact rectangle, OCRs it, and appends the result to a running transcript. Or start an auto-run and it captures, turns the page, and repeats until the document ends. Then Copy all, or Download .txt, and you have a file to paste into Claude or drop into an agent's context. Everything runs locally. Tesseract's wasm build and the language data (~10 MB) are committed into the extension, so there are no network requests at all, no API key, and no host permissions at install — single captures ride on activeTab. The irony of an AI-adjacent tool that never talks to a server was not lost on me, but the pages you're capturing are often exactly the ones you don't want to ship to a third party. Three things turned out more interesting than expected: - MV3 service workers have no DOM and no Worker, so cropping and OCR live in an offscreen document. - The next-page control is stored as a point , not a CSS selector. A point survives DOM re-renders and reaches into cross-origin iframes and shadow roots, which nothing the top frame can express does. Routing it was the fiddly part: window.screenX inside an iframe reports the browser window, not the frame, so frames locate themselves by walking same-origin ancestors, and across an origin boundary the parent hands the offset down by postMessage. - The auto-run waits for each page's OCR before turning. That's what makes end-of-document detection work; a timer-based loop sails past the last page and fills your transcript with copies of it. Limitations: Chrome's own PDF viewer can't be auto-advanced (it's a plugin no extension can inject into, though capturing from it works fine); the region is a fixed rectangle on screen, so resizing or zooming mid-run breaks it; and accuracy tracks the source — crisp rendered text reads at 93-95% confidence, scans need cleanup before they're worth feeding to anything. Tests drive a real headless Chrome over CDP, which had its own surprises: Chrome 137+ ignores --load-extension, and headless can't show the optional-permission prompt, so the suite installs a copy with the grant baked in plus a real toolbar click via Extensions.triggerAction to prove the ungranted path still works. MIT, no build step: https://github.com/thiagotigaz/ocr-it

harsh_patel14

This is handy — I've hit this exact issue prepping documents for LLM context. How's the accuracy on lower quality scans?

tobinfekkes

Also available natively to the OS (Windows) with PowerToys, if you want an alternative to a browser extension. One of the unsung heroes of that library. Jury is still out on which is more trustworthy handling any personal data, Microsoft or Google. Neither.

Barbing

“Pin a region once. Hit a hotkey on every page. Get the whole book as text.” Much better than the old definition of “region lock”, nice. HN isn’t a fan of the generated readmes though, though vibed software (thoroughly used) can be all good.

rickcarlino

Is Tesseract still the best choice for local OCR in 2026? I was always underwhelmed with its real-world performance.

kalinkochnev

Does anyone have suggestions on how I could OCR lots of handwritten math notes with diagrams? I have tons of PDFs waiting for me to manually type them myself and can't justify dedicating weeks to do it.

andreashaerter

If you use a Linux desktop (I am on Fedora), Gradia[1][2] is definitely worth a look as well. It has a similar workflow for taking screenshots and then immediately annotating or editing them, without having to open a separate image editor. And: it provides also an local OCR feature (which is why I comment this here), you can extract text from a screenshot with on-screen OCR using Tesseract with the small button beside the "Crop Image" one. Combined with the syntax-highlighting feature for screenshots of code snippets, the OCR is surprisingly useful in combination if you e.g. quickly discuss some code in a chat when copy is blocked for whatever reason (e.g. somone sent you a screenshot in the first place). [1] https://gradia.alexandervanhee.be/ [2] https://flathub.org/en/apps/be.alexandervanhee.gradia Edit: fixed wrong link index numbers