How the PDF Metadata Editor works
This tool uses two open-source JavaScript libraries to read, modify, and export PDF metadata entirely inside your browser. No file is uploaded to any server at any point in the process.
pdf-lib
pdf-lib handles reading and writing the PDF document. When you upload a file, pdf-lib parses the binary structure of the PDF and exposes the document information dictionary — the object that stores standard properties like title, author, subject, keywords, creator, and producer. After you make changes in the editor, pdf-lib serializes the updated document back into a valid PDF binary which is then offered as a download. The original file on your device is never modified.
PDF.js
PDF.js is Mozilla's open-source PDF renderer. It powers the page preview, rendering each page onto an HTML canvas element at a comfortable zoom level. This lets you confirm you have the right document before committing any metadata changes. PDF.js reads the same file buffer loaded by pdf-lib, so no duplicate upload or parsing overhead is introduced.
What metadata can you edit?
The standard PDF document information dictionary supports title, author, subject, keywords, creator (the application that originally created the document), and producer (the software that converted or exported it to PDF). Beyond these, the editor lets you add arbitrary custom key-value pairs for any additional classification your workflow requires. Modification date is set automatically to the current timestamp when you save.
Privacy
All processing runs in your browser using the Web File API and JavaScript. Your PDF bytes are loaded into memory locally and cleared when you start over or close the tab. Nothing is transmitted over the network.