PDF redact (visual)

When you put a black box on top of text in a PDF, the text object beneath is still there. It's hidden visually — but every word remains in the file's content stream and can be recovered by:

• Selecting all and copying — most viewers happily copy text under a rectangle
• Any text-extract / OCR tool that reads the PDF stream directly
• Removing the rectangle in a PDF editor
• Searching the document for keywords

For situations where motivated parties might receive the file (legal discovery, FOIA / RTI responses, security-cleared docs, anything with regulatory consequences), do not rely on this tool. Use specialist redaction software that flattens the page or removes the content from the stream.

Visual redaction is fine — easy, fast, browser-local — when:

• You'll flatten the result. Run the redacted PDF through /tools/pdf-to-jpg then /tools/image-to-pdf and the text layer is destroyed; only the rasterised image remains.
• You're printing on paper. The rectangle prints solid; the underlying text never reaches the page.
• The audience is casual. A colleague who reads the file in Preview / Acrobat reader won't realise selectable text sits under the box, but a determined recipient will.

Each redaction rectangle is defined by four numbers:

• x from left — distance from the left page edge to the rectangle's left side.
• y from top — distance from the top page edge to the rectangle's top side. (We invert the usual PDF bottom-up convention so you can read coordinates the same way you see the page on screen.)
• width — rectangle width.
• height — rectangle height.

All four use the same unit (mm, in or pt). A standard US Letter page is 215.9 mm × 279.4 mm; A4 is 210 mm × 297 mm. To cover a top-edge header on an A4 doc, try x=0, y=0, width=210, height=20 (mm). Click Add rectangle to stack multiple regions in one pass.

The PDF is parsed and re-drawn locally in a Web Worker. No file bytes, no rectangle coordinates and no metadata are transmitted anywhere. The result is built in your browser's memory and offered as a download. Open DevTools → Network during redaction and confirm: zero outbound requests for the file.

• Password-protected, digitally signed, or archival PDFs may need a specialist workflow before editing.
• Large scans can use a lot of memory, especially on phones or older laptops.
• Check the downloaded file before replacing the original, because compression, OCR, or conversion can change visual details.