Merge PDFs without uploading them

How to merge PDFs privately

1. Drop two or more PDFs on the box above, or click it to pick them.
2. Set the order with the ↑ and ↓ arrows. Remove a file with ×.
3. Click Merge, then download merged.pdf.

What “without uploading” means here

Most online PDF tools send your file to their server, do the work there, and send it back. They usually delete it after a while, but it still leaves your device. FilesStay is a set of static web pages: the merge code is downloaded to your browser along with the page, and it runs there. There is no FilesStay server that receives files.

How you can check

• Go offline. Load this page, turn off Wi‑Fi, then merge. It still works, which it could not if a server were involved.
• Watch the network. Open your browser’s developer tools, go to the Network tab, and merge a file. You will not see your PDF being sent anywhere.

Good for sensitive documents

Contracts, tax forms, payslips, medical records, ID scans: anything you would rather not hand to a third party. The merged file is built in memory and saved straight to your downloads.

Limits

• Password-protected PDFs cannot be opened. Remove the password first in the app that made it.
• Bookmarks and fillable form fields are not rebuilt in the merged file.
• Very large files depend on your device’s memory; a laptop copes with more than a phone.