Redact PDF — securely, free, in your browser
Most online "redactors" leave the hidden text recoverable. SecureRedact removes it for real — defeating the glyph-position leak — and proves it with a before/after audit. Your file never leaves your device.
How it works, in three steps
- Open your PDF — it loads in your browser; nothing is uploaded.
- Mark what to hide — draw boxes or auto-detect SSNs, emails, and names.
- Redact & download — the text is removed, audited as unrecoverable, then saved.
Why other redactors leak — and this one doesn't
The 2022 study Story Beyond the Eye (arXiv 2206.02285) showed that most online PDF redactors leak the redacted text through residual glyph metadata. A black rectangle is not redaction: the characters often remain in the content stream, and even when deleted, the surrounding glyph positions can encode the hidden string. SecureRedact rewrites the content stream, reflows glyph positions, rasterizes the redacted region, and strips metadata and revision history — then runs a recovery audit and blocks the download if anything is still recoverable. See the full explanation →
How SecureRedact compares
Most online redactors upload your file and leave the “redacted” text recoverable (documented in Story Beyond the Eye, arXiv 2206.02285). Here's the difference.
| Capability | SecureRedact | Typical online tool |
|---|---|---|
| Removes the hidden text (not just a black box) | Yes | Often no |
| Defeats glyph-position inference | Yes | No |
| Strips metadata & revision history | Yes | Varies |
| Shows a before/after recovery audit | Yes | No |
| Your file never leaves your browser | Yes | No — uploaded to a server |
| Free | Yes | Often limited / paywalled |
Private by design
100% client-side. No upload, no account, no tracking of your documents. Read our privacy approach →
Frequently asked questions
Is it free?
Yes. SecureRedact is free and open-source. There are no accounts, watermarks, or limits.
Do you upload my file?
No. Everything runs in your browser. Your PDF never leaves your device and is never sent to a server.
Why do other online redactors leak the redacted text?
Most tools just draw a black box over the text but leave the underlying characters — or their glyph positions — in the file, so the hidden text can be extracted or reconstructed. This was documented in the 2022 paper Story Beyond the Eye (arXiv 2206.02285).
Does it remove metadata?
Yes. Redaction strips document metadata (XMP/Info), embedded JavaScript, thumbnails, and collapses incremental-update history so old revisions can't leak.
Can the redacted text be recovered afterwards?
No. After redaction the tool runs a recovery audit on the output and only lets you download if nothing is recoverable. It checks text extraction, glyph-position inference, metadata, and prior revisions.
What is a glyph-position leak?
Even when redaction deletes the characters, the surrounding glyph positions and widths can encode the hidden text's length and identity. SecureRedact reflows or removes those so the geometry can't be used to reconstruct it.
Which files does it support?
Standard PDFs with selectable text. Encrypted or scanned (image-only) PDFs are not supported in this version.
Is the redaction permanent?
Yes — the text and its glyph geometry are removed from the file, not just hidden, and the output is audited to confirm nothing is recoverable before you download.
Does it work offline?
After the page loads it runs entirely in your browser, so redaction works without sending anything to a server. The optional name-detection model downloads once, then is cached.
Is it really free with no catch?
Yes. It's free and open-source, with no account, no watermark, and no upload of your document.