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Annotate & Highlight PDFs

Highlight text and add notes to PDFs in the browser. Export annotations as PDF objects and review the result before sharing.

  • Highlight text and add notes
  • Annotations saved locally in your browser while you work
  • Export the result with PDF annotations embedded

Annotating a PDF lets you highlight text and add notes. OpenPDF exports those annotations through pdf-lib; review the result in the PDF viewer or editor used by the recipient. The annotation state is kept locally while you work and the final export happens when you download.

How it works

  1. Open your PDF. Drop a PDF onto OpenPDF to load it into the annotation view.
  2. Pick an annotation tool. Choose highlight or sticky note from the toolbar.
  3. Mark up the document. Click or drag to apply annotations. Everything stays locally — nothing is sent to a server.
  4. Export with annotations. Download the annotated PDF with all marks embedded as proper PDF annotations.

Common use cases

  • Marking up a contract with highlights and sticky notes during a remote review call.
  • Adding feedback to a design PDF without exporting to a dedicated markup tool.
  • Circling corrections on a scanned document and sending the annotated copy back.
  • Attaching comments to a lease before sending it to a co-tenant for review.

Frequently asked questions

Are annotations embedded as proper PDF annotations?

Yes. OpenPDF exports highlight and note annotations using pdf-lib. Review the result in the PDF viewer used by the recipient.

Can I remove annotations later?

Annotations are saved as objects inside the PDF. A viewer or editor that supports those annotation objects can display or remove them; check the exported file in the target application.

Are my annotations autosaved?

The in-browser state is saved locally while you work. The final export happens when you click Download — at that point the annotated PDF is produced and written to your device.

Is anything uploaded?

No. Annotations are composited with pdf-lib locally in your browser.

Why OpenPDF

OpenPDF is an independent project where PDF document processing runs in the browser using WebAssembly and modern JavaScript APIs. The toolkit includes merge, split, sign, organize, annotate, compress, watermark, page numbers, add image and fill forms. Practical limits depend on the operation, document and device. The page source and privacy policy describe consent controls, analytics, advertising and optional services before you use the tool with sensitive documents.

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