Add two or more PDF files, put them in the order you want, and combine them into a single document — processed entirely on your device.
You can add more files at any time. Nothing is uploaded.
Drag in every PDF you want combined. Order them with the arrows on each row.
Your browser copies every page, in order, into one new PDF using pdf-lib.
Save the combined file. The originals and the merged copy never left this tab.