How it works
As simple and secure as it gets
AirGap Utils opens a PDF from your disk, does its work in the computer's memory, and writes a new PDF where you say. It never talks to a server, because there is no server. It never needs the internet, and it is built so that it cannot use it.
Where your file goes
There is no other arrow: none to a network, to us, to another application, or to a place on disk you did not choose.
Your disk
You choose or drop a file
The app's memory
The tool runs here
Your disk
You choose where to save
What happens to a file
- Step 1
You add it
Choose the file in a dialog or drop it on the window. The app reads it into memory.
- Step 2
The app looks at it
It confirms the file really is a PDF and can be opened, and reads the page count.
- Step 3
You pick a tool
The work happens in memory.
- Step 4
The app checks its own result
It re-opens the new PDF and tests it against the target. Today that is the page count after a merge. Size, searchable text and redaction checks arrive with Version 1.0.
- Step 5
You save it
A normal save dialog. The app never overwrites the original by itself.
- Step 6
The app forgets
When the files are cleared or the app is closed, they are gone from memory. Nothing was written anywhere else.
Keep or rebuild
Two parts do the PDF work: a reader, PDFium, the open-source engine used in Chrome, and a small writer that builds a new page from an image and a layer of text. For each page of a document, the app does one of two things.
Keep
Available nowThe page stays exactly as it is. Text stays text, graphics stay sharp, nothing is recompressed. Merging only ever keeps, and so will splitting and reordering.
Rebuild
Version 1.0The app will draw the page as a picture, compress it, and lay the page's text back on top as an invisible layer, so the page can still be searched, selected and copied. Think of a very good photocopy that you can still search.
| Planned tool | Why rebuilding does the job | Arrives |
|---|---|---|
| Shrink to a size limit | A scanned page is a huge picture. Rebuilding it at a lower resolution makes it much smaller. Only the heavy pages are rebuilt. | Version 1.0 |
| Redaction | A rebuilt page contains only pixels and the text chosen to go back. The words under a redaction box are in neither, so they are removed, not covered. | Version 1.0 |
| PDF/A | A page made of one image and embedded text meets the archival standard's rules by construction. | Version 1.1 |
The trade-off, said out loud: a rebuilt page is no longer vector. Zoom far in and the text is slightly soft, and screen readers see plain text without headings or structure.
Why the app checks its own work
Most PDF tools do the operation and hand you the file. AirGap Utils re-opens what it made and tests it.
From Version 1.0, if you ask for 5 MB and the result is 5.3 MB, it will not hand you a 5.3 MB file and let the upload fail. It will try again, or split the document, or tell you it cannot be done. If a redaction leaves a word behind, saving will be blocked.
The checks are things a computer can measure: size, page count, whether text can be extracted, whether a redacted word still appears. They are not a judgment about whether a court or portal will accept the file.
Nothing leaves the device
Three layers, from the inside out. Any one of them is enough to stop a connection.
1. The code never calls the network
An automated check on every code change fails if networking code appears in the app's own code.
2. A guard inside the app refuses connections
When the app starts, it switches off the ability to open a connection. The System check screen shows that the guard is on.
3. The operating system blocks the app, where it can
On a Mac the app runs in Apple's sandbox without permission to use the network. On Android it never asks for the internet permission. On Windows the installer will add a firewall rule with Version 1.0. On iPhone there is no such switch, so layers 1 and 2 do the work.
A precise point for technical buyers: one of the components we use contains code for downloading PDFs from web addresses. We never use that feature, we have disabled it, and the guard would refuse it. A reviewer who inspects the app may find it, and should hear it from us first.
Your IT team can verify all of this themselves. The steps are on the security page.
Nothing is left behind
- Files are held in memory while the app works on them.
- The app writes nothing to disk except the file you save.
- There is no recent-files list, no cache of pages and no thumbnails on disk.
- On a phone, the system's file picker makes a temporary copy. The app deletes it as soon as it has read it.
- Your original file is yours and stays where you keep it. The app does not protect, move or delete it.
What “air gap” means here
An air-gapped computer is one that is physically disconnected from networks. AirGap Utils does not require that. It means the app behaves as if it were air-gapped: the computer can be online, and the app still sends nothing. It also runs perfectly well on a computer that really is disconnected.
Because the app cannot go online, it cannot update itself. Updates arrive as a new version that your IT team installs, the same way they install the first one.
Try it free on your own machines
Free trials are open to businesses. No account to create, and your documents never leave your devices while you try it.