pdfviz

Check a PDF for redaction leaks

or drop one here

What this check can find

Opaque dark rectangles with selectable text underneath, plus document metadata, annotation text, attachments and hidden layers that need review.

It does not certify a PDF as safe. Unusual covers and words stored only inside images can require a manual review.

Choose a PDF first.

A black box is not proof that the text underneath was removed. This check reads the PDF drawing instructions, outlines supported cover boxes and reports any selectable text still below them. It also lists private data outside the page. The PDF never leaves this tab and is not changed.

How to check a PDF for redaction leaks

  1. Choose a PDF

    Press Choose a PDF, or drop one on the page. The file stays in this browser tab and is never uploaded.

  2. Inspect every page

    The checker reads page drawing instructions, finds opaque dark rectangles and compares each one with the selectable text layer below it.

  3. Review recovered text

    Pages with cover boxes appear in the report. The report marks any box with live text underneath and shows the recovered text in full so you can see exactly what leaked.

  4. Check the limits

    Read the metadata, annotation and hidden-layer findings, then review the stated limits. No leak found is not a safety certificate.

What this redaction checker finds, and what it cannot

A PDF page is a stack of drawing instructions. A failed redaction leaves the original text in that stack and adds a dark rectangle above it. The page looks clean, but copying the text layer or reading the content stream reveals the hidden words. This tool looks for that specific failure and shows the text it can recover.

The result has a hard boundary. A black photograph, an unusual clipping path or a cover made from many small shapes may not look like one vector rectangle to the parser. Text burned into an image is also out of reach. The tool states these limits in the report so you know what it checked and what it did not.

If the checker finds leaked text, run the file through the redact PDF tool to remove the content permanently. After redacting, you can check again to confirm. To strip metadata that may also identify you, follow up with remove PDF metadata or a privacy scan.

When you need a redaction checker

Verifying a redaction before sharing. If you or a colleague drew black boxes over sensitive text in a standard PDF editor, run the file here before sending it. The checker tells you whether the text underneath is actually gone.

Quality control for legal filings. If the filing rules require real redaction, a cover is not enough. Check each file before submission so a hidden text layer does not travel with it.

Reviewing files from third parties. Before publishing a document someone else redacted, verify their work. A visual check is not enough because the text layer is invisible to the eye.

Auditing your own process. If you redact files regularly, run samples through the checker to confirm your workflow removes content rather than hiding it.

Rechecking an old file before it travels further. A file redacted months ago is about to be shared more widely. Run it here first to confirm the text layer stayed clean.

How the redaction checker reads a PDF

The checker does not look at the page the way a human does. It reads the raw drawing instructions - the content stream that tells the reader what to draw and in what order. Reading the instructions is how the checker finds text that is visually hidden but still present in the file.

It walks every page, identifies filled rectangles that could be cover boxes, and then checks whether selectable text exists at the same coordinates. If text is found beneath a box, the checker extracts it and displays it in the report. This is text that a reader could copy by dragging through the box, or that a script could extract from the raw file.

The checker also scans outside the page for metadata, annotations and hidden layers that may carry private information. It states its limits clearly: covers made from photographs, unusual clipping paths or many small shapes may not register as single rectangles, and text burned into images is pixels rather than instructions. Knowing what the tool cannot see is as important as knowing what it can.

Questions about checking PDF redactions

Is my PDF uploaded?
No. The check runs entirely in this browser tab. The file is not sent to a server and is not modified.
What does the checker look for?
It reads the PDF drawing instructions, finds opaque dark rectangles and compares each one with the selectable text layer below it. It reports any text it can recover.
What does "no leaks found" mean?
It means the checker found no selectable text under the cover boxes it could identify. It is not a guarantee that no information leaked, because covers the parser cannot recognise are out of reach. Read the stated limits in the report.
Can the checker fix a bad redaction?
No. This tool only reports. To remove leaked text, use the redact PDF tool, then check again to confirm.
Does it check metadata too?
It lists private data outside the page such as author and producer fields. For full metadata removal, use remove PDF metadata or privacy scan.
Does the checker work on scanned PDFs?
It checks the text and drawing layers. Text burned into a scanned image is out of reach because it is pixels, not instructions.
Is there a file or page limit?
There is no server-side cap: processing happens in your browser. Very large files are still bound by your browser tab's memory and may take longer on slower devices.

The other pdfviz tools

All of them run in a browser tab like this one, and none of them needs an account.