Merge PDF files without uploading them anywhere
A signed contract in three separate scans, a visa application that wants one combined document, invoices that need to arrive as a single attachment. Merging PDFs is one of those small chores that comes up constantly. The problem is that the documents involved are often exactly the ones you should not hand to a random website: agreements, medical records, tax paperwork. This tool merges PDFs entirely inside your browser using pdf-lib, a pure JavaScript library. Your files are read from disk, stitched together in your browser’s memory, and downloaded as merged.pdf. No server ever receives a byte of them. Pages keep their original size and orientation, and the files are combined in exactly the order you select them.
How it works
- Select or drop your PDF files in the order you want them combined.
- The tool joins them front to back. First selected file first.
- Download merged.pdf straight from your browser’s memory.
Frequently asked questions
How do I control the page order in the merged file?
Files are combined in the order you select or drop them. If the order is wrong, run the merge again after arranging the files in the sequence you want. There is no upload delay.
Do my contracts or documents get uploaded to a server?
No. The merge runs on pdf-lib, a JavaScript PDF library executing entirely in your browser. Nothing is transmitted. You can open your browser’s network tab and watch, or disconnect from the internet after the page loads and the tool keeps working. For signed agreements and financial documents, that is the whole point.
Are bookmarks and the table of contents preserved?
No. pdf-lib copies the page content, including text, images, fonts, and annotations, but it does not carry over the document outline or bookmarks. If the source PDFs rely on a clickable table of contents, you will need to rebuild it in a desktop editor.
Is there a limit on how many PDFs or how large they can be?
No fixed limit. Because everything happens on your machine, the practical ceiling is your device’s memory. Merging dozens of ordinary documents is no problem on a typical laptop; a stack of enormous scanned volumes may push a low-memory device.