The PDF Merger combines selected files in browser memory. This removes a file-processing upload step, but does not guarantee regulatory compliance or protect a compromised device.
Start with a reproducible sample
Create two small PDFs with visible labels A1, A2 and B1. Select them, arrange their order using the available controls and merge. Open the download in a separate viewer. Confirm three pages in the expected order, with selectable text where the original had selectable text.
Repeat with your intended files after the sample behaves correctly. Keep the originals. Inspect rotation, page sizes, annotations, links and important form fields. Combining documents does not preserve the validity of signatures over the original file bytes.
Verify local processing
Open developer tools, select Network and operate the merger with sample files. Inspect outgoing request payloads. Requests for application code differ from uploading PDF content. The separate AI assistant and contact form send messages to servers: do not paste document contents into them as part of a privacy test.
Practical limits
Large documents consume device memory. Mobile browsers may terminate a tab before a desktop browser would. Try a smaller set if processing fails. Encrypted or malformed files may need a different workflow. There is no universal promise that every PDF feature survives a rewrite.
The application uses pdf-lib for document manipulation. Keep original files as a recovery copy and verify the exported document before distributing it. For size reduction, the PDF Structure Optimizer rewrites objects and removes metadata; it does not recompress embedded photographs.