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Compress PDF

Annotate PDF

Stamp an ink line or a highlight rectangle on a PDF page by coordinates (PDF units, origin lower-left). Your files never leave your device; all processing is local and private.

Private by design
Your files never leave your device. All processing happens locally in your browser — no uploads, no servers.

Drop your PDF here

or click to choose a file

Your files never leave your device.

Stamp a straight ink line or a highlight rectangle on a PDF page. Coordinates are PDF units, origin lower-left. All processing is local — the file never leaves your device.

Annotate PDF draws a straight ink line or a filled rectangle on a chosen page. Enter coordinates in PDF points (origin at the bottom-left), pick a color, line width and opacity, and the mark is written into the page content with pdf-lib. Everything runs locally in a Web Worker; you download the marked-up PDF and nothing is uploaded.

How it works

How to use Annotate PDF

  1. 1
    Drop your PDF. Drag and drop a PDF, or choose one from your device.
  2. 2
    Choose line or rectangle. Enter start and end points for a line, or x/y/width/height for a rectangle, then set color, width and opacity.
  3. 3
    Run Annotate PDF. The mark is drawn into the selected page's content stream locally with pdf-lib.
  4. 4
    Preview and download. Check the preview, then download the annotated PDF.

Features

What this tool does

  • Straight ink lines for underlines, dividers and signature lines
  • Filled rectangles for highlights and redaction-style boxes
  • Color, line width and opacity controls
  • Page selection with a live preview
  • No upload — annotations stay on your device

Limitations

Things to know

  • Coordinates are entered as numbers; freehand canvas drawing is not available yet
  • Marks are baked into page content rather than added as removable PDF annotations
  • A filled rectangle visually covers content but does not securely redact the underlying text
  • Modifying a digitally signed PDF can invalidate its existing signature

FAQ

Frequently asked questions

Can I draw freehand?

Not in this version. The tool provides deterministic line and rectangle inputs so the mark lands exactly where you specify. A freehand canvas is a future enhancement.

Does a black rectangle redact the text underneath?

No. A rectangle is a visual overlay; the text remains in the file and can still be extracted. For secure redaction, remove the content itself with a dedicated redaction tool.

What coordinate system is used?

Coordinates are PDF points with the origin at the bottom-left of the page. One inch is 72 points.

Are my annotations uploaded?

No. The marks are drawn locally in a Web Worker; the PDF never leaves your device.