How to merge PDF files without uploading them

Why merging happens locally

Merging a PDF only requires reading each file's page objects and writing them into a new document. That work needs no server, so PDFzy does it inside your browser tab using your device's processor.

The practical benefit is privacy: signed agreements, medical scans and payroll documents never leave your machine, so there is no copy on someone else's server to worry about.

Getting the page order right

Order is decided by the list, not by file names. After you add your files, use the up and down controls to arrange them, then merge.

• Add the cover or contract first so page 1 is what a reader expects.
• Group scans of the same document together before merging.
• If a file is upside down, rotate it first, then merge.

What merging does not change

Text stays selectable, links inside pages are preserved, and page sizes are kept as they are — a mix of A4 and Letter pages will still be mixed in the result. If you need a consistent size, convert the pages to images and rebuild the PDF at one size.