Do online PDF tools upload your files? We tested 10 other tools.
Tested on 18 October 2026
Many online PDF tools work the same way: you pick a file, it travels to their server, their server does the work, you download the result. Your document leaves your computer. Some sites say this plainly.
PDF Utils works differently. The processing code runs inside your browser, so your file is processed on your device. We are not asking you to take our word for that. We ran a test.
How we tested
On October 18, 2026, in Chrome 155, we opened the compress tool on PDF Utils and on 10 other popular PDF sites. On each page, once it had loaded, we recorded the network requests, then attached the same small test PDF and ran the compression. What counted as an upload: a request carrying the file. We looked for requests whose size matched our file and for any request carrying it, and we noted the address each one went to.
What we saw
PDF Utils: no upload. The compression finished normally. After the file was attached, the page made a few requests - for its own code, a font and an ad ping - and we saw none of them carry the file. (When it first opens, the page also loads ads, a consent banner and analytics.)
Every other tool we tested sent the file to a server:
| Tool | Uploaded? | Where |
|---|---|---|
| iLovePDF | Yes | api58.ilovepdf.com/v1/upload |
| Smallpdf | Yes | the raw file sent to their cloud storage, then a processing task created on task.smallpdf.com |
| PDF24 | Yes | filetools34.pdf24.org - posted the moment it was attached, before we clicked anything |
| PDF2Go | Yes | www18.pdf2go.com upload endpoint |
| Foxit | Yes | foxit.com/online-tools-api/upload |
| SodaPDF | Yes | api-gw.sodapdf.com |
| Adobe Acrobat online | Yes | processed on Adobe's servers; their own result page says the file will be "deleted from our servers" |
| PDF Candy | Yes | s34.api.pdfcandy.com (their server rejected our minimal test file, which shows our file reached their server) |
| PDFresizer | Yes | a plain upload form; the result page was rendered by their server |
| Online2PDF | Yes | a plain upload form to their server |
What this means
Uploading your file is not a scandal. These tools need your document on their server because that is where their software runs. But it means your contracts, medical letters or bank statements sit on someone else's computer, under someone else's privacy policy, for however long they keep them. With PDF Utils the software comes to your file instead of the other way around.
One honest limitation
We tested once, with one small PDF, on October 18, 2026. Sites change how they work, and a tool we did not test may behave differently. This method can also miss uploads that are chunked, compressed or encoded. What we can stand behind is exactly what we recorded that day. PDF Utils runs its processing in your browser, and in our test we saw no request carrying the file.
Check it yourself
You do not have to take our word for it. Open your browser's developer tools (F12), go to the Network tab, then attach a PDF in any of these tools and look for a request about the size of your file. If one appears, your file was uploaded. That is a quick check, not proof: a site can send the file in chunks or compressed, so the request size can differ. When we did the same on PDF Utils, we saw no such request. One caveat: ads and fonts still load when a page first opens, so you will see some requests that have nothing to do with your file.