What you are usually merging
The documents people combine are contracts, bank statements, medical records, identity documents, and application packets. That is the nature of the task — you merge things that have to be submitted together.
Deletion after an hour limits how long a copy exists. It does not remove the transfer itself, the provider's logs, or the question of which jurisdiction the server sits in. For a scanned passport, those are reasonable things to care about.
What browser-side merging changes
A browser can read PDF files and write a new one without a server. The file is opened from your disk by the page, combined in memory, and saved back to your downloads. Nothing is transmitted.
This is not a claim that needs trust in a policy — with the tool open, you can disconnect from the network entirely and it still works.
What it cannot do
Browser processing uses your device's memory, so very large files can fail where a server would succeed. Splitting the job into a few smaller merges usually solves it, and a desktop machine has more headroom than a phone.
Password-protected and encrypted PDFs will not open. Remove the protection with software you are authorized to use, then merge.
What merging does not do
Merging concatenates documents. It does not re-encode them, so the result is roughly the sum of the inputs — a merge will not make a large submission smaller, and a set of high-resolution scans stays large. Compress first if there is a size limit on the other end.
It does not reorder pages inside a file either. You control the order the documents are combined in, but a document whose own pages are out of order arrives that way. Fix that in the source file before merging.
Scanned pages remain images. If the recipient needs selectable or searchable text, the scans need optical character recognition, which is a separate step that merging will not perform.
Before you merge
- Confirm the order — pages are combined exactly as listed, and reordering after the fact means merging again
- Check the page count of the result against the sum of the inputs
- Open the merged file once before submitting it; a document that fails to render is better found now
- Keep the originals until the submission is accepted