Highlight PDF
Highlight PDF turns text you drag across into a yellow highlight, added with mupdf in your browser as a standard PDF annotation any reader can remove later.
Drag and drop, or click to upload a PDF
At a glance
- Accepts
- One PDF file that has a text layer (not a scan)
- Outputs
- The same PDF with yellow highlight annotations on the text you picked
- Where it runs
- Entirely in your browser, on your device
- What leaves your device
- Nothing - the file never leaves your device
- Limits
- Needs real text - a scanned page has nothing to select until it's been through OCR
- Account
- Not required - there is no sign-up
- Price
- Free, with no watermark and no usage cap
Highlight PDF marks up a PDF the way you would with a pen: drag across the words you care about and they turn yellow. The pages are rendered and the text selection is resolved by mupdf running inside this browser tab, so the file is never uploaded - and because the highlights are saved as standard PDF highlight annotations, the text underneath stays selectable and searchable, and any PDF reader can remove them later.
How to use it
- Drag and drop, or click to upload a PDF.
- Drag across any text on the page to highlight it. Use Previous and Next to move through the document.
- Got one wrong? Undo (or Ctrl+Z) removes the last highlight, and Clear all removes every one.
- Click "Download Highlighted PDF" when you're done.
Frequently asked questions
Is my PDF uploaded to a server?
No - the pages are rendered, the text selection is resolved, and the highlights are written back into the file by mupdf running inside your browser tab. The PDF never leaves your device.
Can I undo a highlight?
Yes. Undo removes the last highlight you made (Ctrl+Z, or Cmd+Z on a Mac, does the same), and Clear all removes every highlight at once. Nothing is written to the file until you download it.
Can I remove a highlight after downloading?
Yes - each one is saved as a standard PDF highlight annotation, so Acrobat, Preview, and other PDF readers list it and can delete it. It isn't painted onto the page.
Nothing highlights when I drag - why?
The page has no text layer, which is normal for a scan or a photo of a document. Highlighting follows the real words in the file, so a page whose words are only pixels has nothing to select. Run the file through OCR first.
Does highlighting change the text or the layout?
No. The page content is untouched - the highlight is added on top as an annotation, so the text stays selectable, searchable, and exactly where it was.
Can I pick a different colour?
Not yet - highlights are yellow, the colour every PDF reader shows the same way.
What's the highlighted file called?
Your original filename with -highlighted added, like contract-highlighted.pdf.