Combine PDFs into one file. Runs in your browser — nothing is uploaded anywhere.
Two or more files. They merge in the order listed below.
Merging PDFs is a local file operation. It needs no server, no account and no subscription — a browser can do the whole thing on your own machine in a fraction of a second.
The well-known services charge a monthly fee for it anyway, and to use them you upload your documents to someone else's computer. For a contract, a medical record or a tax return, that is a genuine cost even when the price is zero.
This page loads a PDF library, does the work in the tab, and hands you the result. You can check that claim: open your browser's network tab and watch. Nothing goes out.