Free PDF Tool · Edit

Highlight PDF

Run highlight pdf in your browser. Free, private, no signup — your selected files are processed in your browser and are not uploaded to our server.

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Drop your file here

or click to browse from your device

Accepts: .PDF

About this Highlight PDF

Highlight PDF text runs that contain your search text. Choose the highlight color, opacity, case-sensitivity, and optional page range.

Useful for marking important passages, drawing attention to specific data, or annotating reports.

Your privacy is the default. Your selected files are processed in your browser and are not uploaded to our server; all processing happens client-side using browser PDF libraries such as pdf-lib and PDF.js where needed. Closing the tab clears the working session from this page; downloaded files remain on your device.

This tool is free to use with no signup required. Large files may be limited by your browser’s memory and device performance. Part of PDF Tools Base, a privacy-first collection of 161 PDF utilities. Bookmark the page for next time, and explore related tools in the footer below.

How to use the Highlight PDF tool

  1. Drop your PDF.
  2. Enter the text to highlight, then choose color, opacity, case-sensitivity, and optional page range.
  3. Click Process and download.

Why use PDF Tools Base?

100% Browser-Based

Highlight PDF processes selected files in your browser. Your selected files are processed in your browser and are not uploaded to our server.

No Server Upload, No Signup

Your selected files are processed locally in your browser. No account, no server upload, no email needed.

No Watermark Ever

Outputs are clean. We never stamp our brand or a paywall watermark on your files.

Free to Use

No accounts and no signup. Use the tool as much as you need within reasonable browser limits.

Works on Every Device

Windows, Mac, Linux, iPhone, iPad, Android, Chromebook. Any modern browser.

Built on Open Source

Powered by browser-side PDF libraries such as pdf-lib and PDF.js, depending on the operation.

Common uses for highlight pdf

Mark key data

Yellow for important figures, green for verified.

Study notes

Highlight definitions in textbook PDFs.

Review comments

Visually flag passages for discussion.

Frequently asked questions

Is Highlight PDF safe to use?

Yes. Everything happens in your browser. Your selected files are processed in your browser and are not uploaded to our server. Closing the tab clears the working session from this page; downloaded outputs remain on your device until you delete them.

Do I need to register or sign in?

No. No account, no email, no sign-up. Open the page and start using the tool immediately. Free to use, no signup needed.

Is there a watermark on the output?

No. PDF Tools Base never adds a watermark or branding to your output. Your final file is clean — just what you produced from the original.

Is there a file size limit?

There is no fixed limit. Files are processed in your browser, so RAM, page count, and file complexity affect what is feasible. Phones may struggle with large PDFs; try splitting first or use a desktop browser.

Does this work on mobile devices?

Yes. The tool works on all modern mobile browsers: Chrome on Android, Safari on iOS, Firefox, Edge, Brave. The drag-and-drop also accepts files from your phone’s file manager.