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This clears the information a PDF carries about itself rather than anything on its pages. That is more than the author field people expect: the document properties, the XMP packet, the private data an editor left under /PieceInfo, per-page metadata, and the identifier in the trailer. The file is read first, so the result can tell you what was actually found and what was removed.

Use it before a document leaves your organisation: a tender response that should not name the person who drafted it, a CV that would otherwise carry your employer's file server path, or a template you are publishing that still credits the client you built it for.

วิธีทำงาน

1. Drop the PDF onto this page.
2. Leave Keep the title off unless the title is deliberate and public - it is often a file path or a working name nobody meant to publish.
3. Leave Keep the dates off if you are anonymising. The timestamps are a fingerprint, and clearing them clears the document identifier with them.
4. Press Remove metadata.
5. Read the report. It lists what was found in the file and what was taken out, so nothing to remove is a real and useful answer.

The gap between what people expect this to remove and what a PDF actually carries is the reason the tool exists. A file routinely records the application that produced it, the operating system account signed in at the time, the full path the source document lived at, every editing session's timestamps, and - in anything that passed through Illustrator or InDesign - a private data blob under /PieceInfo that no PDF reader will ever display to you.

The trailer identifier matters more than its obscurity suggests. It is a pair of hashes derived from the file and the moment it was written, and it survives every cleanup tool that only clears the document properties dialog. Two files carrying the same first identifier are demonstrably versions of one original, which is precisely what someone anonymising a document does not want to leave behind.

Removal here means removal, not blanking. Each entry is deleted from the file and anything only that entry pointed at goes with it, so the values are not left sitting in the bytes for anyone who opens the file in a text editor. When the properties dictionary ends up empty it is dropped entirely, because an empty one is itself a small signal about how the file was made.

This does not touch what is written on the pages. A name in a letterhead, a signature block, a footer with a file path - all of that is content, and content is what Redact PDF is for. Metadata removal makes the file anonymous; it does not make the document anonymous.

The reading and the rewriting both happen in your browser with pdf-lib. There is a pleasing consistency in that: a tool whose job is to stop a document telling strangers about you would be a strange thing to run by sending the document to a stranger.