A black rectangle is not redaction

Drawing a black box in Preview, Acrobat or Word puts a shape on top of the text. The words are still in the file. Anyone can select them, copy them out, or open the file in a text editor and read them. That is how redacted court filings, government reports and contracts keep leaking.

Blackline does the only thing that actually works: it rebuilds every page as a flat image with your boxes burned in, then writes a fresh PDF from those images. There is no text layer left to recover, because there is no text layer at all. It also drops the document metadata (author, title, producer, creation dates) on the way out.

Nothing is uploaded — this is not a website that processes your file

Every online redaction tool asks you to upload the document to their server. For a payslip, a medical letter, a client contract or a police record, that is the whole problem. Blackline is a single page of JavaScript: your PDF is opened by your own browser, on your own machine, and no part of it is ever transmitted. You can disconnect from the internet, redact the file, and reconnect afterwards.

Pricing

One payment, no subscription. A licence key arrives instantly; paste it below and the page limit is gone on every device you use.

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Questions people actually ask

Can the redacted text be recovered?

No. The output pages are images. The characters you covered were never written into the new file, so there is nothing to select, copy, grep or undo.

Does the output PDF stay searchable?

No — and that is the trade. Flattening is what makes the redaction real. If you need a searchable copy, keep your original; the redacted file is the one you send out.

Does it remove metadata too?

Yes. The new PDF is written from scratch with empty title, author, subject, keywords, creator and producer fields. For images, re-encoding drops the EXIF block, including GPS coordinates.

Does it work offline?

Yes. Load the page once and it is cached; after that it works with no connection at all. That is also how you can prove to yourself that nothing is being uploaded.

What file types can I redact?

PDF, JPEG, PNG and WebP. Scanned documents work the same way as digital ones.

Is there a size limit?

Only your computer's memory. There is no upload, so there is no upload cap.

Guides

• Why redacted PDFs leak: how a black box gives the text back
• How to redact a PDF for free, without uploading it anywhere
• How to remove PDF and image metadata before you send a file
• Redaction checklist for GDPR, HIPAA and disclosure

Also free, from the same shelf

ShrinkKit — compress and strip EXIF from a whole folder of images, also entirely in your browser.