Show HN: Merge multiple PDFs into one using WebAssembly Posted by kickbeak on Thursday February 18, 2021 @11:52AM from the show-hn dept. http://localpdf.tech/ ( 3 comments | 11 points | on HN )
Off topic: If you're on a Mac, you can do a lot of PDF manipulation right from Preview.
https://support.apple.com/en-us/HT202945