Files are processed entirely in your browser using pdf-lib โ nothing is uploaded to any server.
Combining multiple PDF files into one is a common need โ merging scanned documents, combining multiple reports into a single submission, or putting together a set of certificates or forms. This tool joins your selected PDFs in the order you add them, producing one continuous PDF with all pages from every source file included sequentially.
Everything happens directly in your browser using a JavaScript PDF library (pdf-lib) โ your files are never uploaded to any server. This means it works even with sensitive or private documents, and processing is generally fast since there's no upload/download round-trip involved.
There's no hard-coded limit in the tool itself, but very large files or a very high page count may slow down processing since everything runs in your browser's memory rather than on a server.
Currently files are merged in the order you select them โ if order matters, select or drag them into your intended order before choosing 'Merge PDFs', or merge in smaller batches sequentially if you need to insert a file in the middle later.
No โ merging happens entirely client-side (in your browser) using pdf-lib. Files are never sent to KiTools' servers or any third party, which makes this safe to use even for confidential or private documents.