Merge or split a PDF without uploading it
Why most “free PDF” sites upload your documents, and how to combine or extract pages locally in the browser.
The upload problem
The usual PDF websites ask you to drop a file, wait for a spinner, then download a result. That path sends the document to someone else’s server — fine for a public flyer, less fine for a contract, passport scan, or payroll PDF.
Modern browsers can do the same work on the device. Libraries such as pdf-lib read the file you selected, copy pages in memory, and write a new PDF you download. Nothing has to leave the tab.
When to merge vs split
Merge when you have several files that should become one attachment: cover letter + CV, or scanned chapters. Keep the files in the order you want them to appear.
Split when you only need some pages: the first two of a 20-page statement, or page 7 on its own. Enter ranges like 1-3, 7. The original file on disk stays untouched; you get a new download.