What PDF metadata gives away
Besides its pages, a PDF carries information about itself. Most of it is written automatically by the software that made the file, so people rarely know it is there.
- Author. Usually the name on the account of the computer or Office licence that created the document. Often a real person's full name.
- Title and subject. Frequently a working title, the original file name, or the name of the person the document is about.
- Created with / PDF made by. The software and version: "Microsoft Word for Microsoft 365", a scanner model, an accounting package.
- Dates. When the document was created and last modified, to the second, often with a time zone.
- The XMP record. A second, separate block of metadata in XML. It repeats the fields above and can add more: editing history, document IDs that link versions, and custom fields some software adds.
- Attachments and old revisions. Files embedded inside the PDF, and earlier versions of edited objects left behind by "incremental save".
Drop your PDF into the tool above to see every field it carries, then remove or rewrite them. Documents up to 5 pages are free. Check a PDF →
How RedactKit removes it
Open the PDF in the tool above and the Metadata tab lists every document-information field and every XMP property it found, plus attachments, JavaScript actions and page-level metadata. Press Remove all metadata and RedactKit writes a copy without:
- the document information dictionary (title, author, subject, keywords, creator, producer, dates and any custom fields),
- the XMP metadata packet,
- page-level metadata and application data ("PieceInfo"),
- attached files and document-level JavaScript,
- every object nothing in the file refers to any more, which is where old revisions hide.
Pages, links, bookmarks and form fields are kept as they were, so the cleaned PDF looks and works the same.
Why "old revisions" matter
When a PDF is edited and saved, many programs append the changes to the end of the file instead of rewriting it. The old title, the old author, even an old version of a page can still be in the file's bytes, just no longer pointed to. A viewer won't show them, but anyone who opens the file in a text editor can read them. RedactKit rebuilds the file from what is actually used, so those leftovers are dropped. The test suite checks this with a file whose title was changed by an incremental save: after cleaning, the old title is nowhere in the bytes.
Redaction removes metadata too
If you are redacting a document anyway, you don't need a separate step: every redaction export is a new file with no metadata, bookmarks, comments or attachments at all. The Metadata tab is for when you want to keep the pages exactly as they are and only clean the information around them.
Check the result, whatever tool you use
Metadata removal is easy to do halfway. Some tools blank the document information fields but leave the XMP record, which holds the same data. Some write their changes as an incremental update, so the old values stay in the file's bytes behind the new ones. Open the cleaned file here (viewing metadata is always free and changes nothing) and the Metadata tab will show you anything that is left.
Related: PDF metadata editor · Remove personal information from a PDF · How to redact a PDF