Question 1

What does this tool actually do, and what doesn't it do?

Accepted Answer

It draws filled black rectangles on top of the PDF page at the coordinates you select, then saves the result. The rectangles are part of the page content (not a removable annotation layer), so they survive printing, screenshots, and standard PDF viewers. What it does NOT do: it does not strip the underlying text from the PDF's content stream. A determined user with a PDF editor or certain viewers may still be able to extract the original text via copy-paste or text extraction. For anti-forensic redaction (legal evidence, court filings, leaks-resistant work), use desktop software that performs true content-stream surgery.

Question 2

When should I use this vs a desktop redaction tool?

Accepted Answer

Use this when the redaction is for visual privacy — screen sharing on a call, printing a document with a salary line covered, sharing a contract draft over chat, or sending a screenshot of a PDF page. The black rectangle reliably covers the text in every common viewer. Use a desktop tool (Adobe Acrobat Pro Redact, free OSS like qpdf+ghostscript pipelines, or government-grade tools) when the recipient might forensically attempt recovery, when the PDF will be filed in legal proceedings, or when policy requires stream-level removal.

Question 3

Are my files uploaded anywhere?

Accepted Answer

No. Redact PDF runs entirely in your browser via PDF.js and pdf-lib. Your file never leaves your device — useful for documents you should not be uploading to any third-party server, even when the redaction itself is only visual.

Question 4

Can I redact images and signatures, not just text?

Accepted Answer

Yes. The black rectangles cover anything underneath — text, images, signatures, stamps, scanned content. Visual coverage works the same way regardless of what's beneath the rectangle.

Question 5

Is there a file size limit?

Accepted Answer

Soft limit of 100 MB per file for browser memory reasons. Larger files may work but can slow down older devices. For very large PDFs, split first and redact each part.

Question 6

Does this work for scanned PDFs?

Accepted Answer

Yes for the visual redaction — the black boxes cover the scanned image just like they would cover text. There is also no underlying text content stream in a scan to worry about (which actually makes scans harder to recover from than text-PDFs). Run OCR first if you need the redacted file to remain searchable elsewhere.

Question 7

Will the redacted PDF reveal the original text via copy-paste?

Accepted Answer

If the source PDF has a text content stream (most digitally-generated PDFs do), copy-paste in some viewers may still surface the underlying text. Black rectangles cover the visual layer; the text layer is preserved. If copy-paste recovery is a concern for your use case, treat this tool as visual privacy only and use a desktop content-stream redactor instead.

Redact PDF — Cover Sensitive Text in Your Browser

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