Does iLovePDF upload my files?

In our test of its Compress PDF tool, yes: the whole file was sent to api32.ilovepdf.com as soon as it was chosen, before the Compress button was clicked.

Does Adobe Acrobat online upload my PDF?

Yes. In our test, the file was sent to unity-ew1.adobe.io before the page moved to acrobat.adobe.com, where it then appeared as a stored document.

How can I tell if a PDF website uploads my file?

Open the browser's developer tools (F12), go to the Network tab and choose a PDF. A request about as large as your file means it was uploaded; no such request means the work happened in your browser.

Is it safe to use online PDF tools for confidential documents?

Large services publish deletion and security policies, but an uploaded file depends on them. For sensitive documents, a tool that processes the file in your browser removes that risk.

Do online PDF tools upload your files? A network test of 7 sites

Most online PDF tools look the same: you drop a file, wait, download the result. What you cannot see is where the file goes. We gave the same test PDF to the Compress PDF tool of popular sites and recorded every request the page made, to see whether the file left the browser.

Tested on 6 October 2026, in Chromium on Windows, without an account and with optional cookies refused.

Results

6 of the 7 sites measured sent the whole file to their servers as soon as it was chosen, before the Compress button was even clicked. One processed it without sending it.

Site	File sent to a server?	Request that carried the file	Data sent / test file size
PDFDogOnly the page, its scripts and the compression engine were downloaded. No request carried the file, before or after compression.	No	—	0 / 552,786 bytes
iLovePDF	Yes, on selection	api32.ilovepdf.com/v1/upload	553,945 / 553,738 bytes
Adobe Acrobat onlineThe file was sent before the page moved to acrobat.adobe.com, where it then appears as a stored document.	Yes, on selection	unity-ew1.adobe.io/api/v1/asset/upload	557,214 / 557,165 bytes
PDF24 Tools	Yes, on selection	filetools47.pdf24.org/client.php?action=upload	560,947 / 560,947 bytes
Sejda	Yes, on selection	www.sejda.com/api/files/upload	555,016 / 554,745 bytes
PDF2Go	Yes, on selection	www34.pdf2go.com/v2/dl/web7/upload-file/…	551,825 / 551,825 bytes
Soda PDF	Yes, on selection	api-gw.sodapdf.com/api/processing/saas/upload	558,408 / 558,396 bytes
SmallpdfNot measured: the page ignores a file given by our test script, and the test only uses files given that way. Check it yourself with the method below.	Not measured	—	—

Compress a PDF without uploading it

How we tested

A one-page PDF of about 550 KB was generated in the page for each test: a 1600 × 1200 photo-like image and the marker text "PDFDOG-PRIVACY-TEST-2026". It contains nothing personal.
Before choosing the file, a script recorded every request made by the page (fetch, XMLHttpRequest and beacons), with the size of the data it sent. The browser's own network log was read as well.
The file was given to the page's file picker, exactly like a file chosen by hand. We then waited without clicking anything else.
A site counts as "sent to a server" when one request carried at least as many bytes as the file itself (the file plus a few form fields).

Check any PDF site yourself in one minute

Open the tool page in Chrome, Edge or Firefox and press F12 (or right-click → Inspect), then open the Network tab.
Choose a PDF that is not confidential, larger than 1 MB so it stands out.
Sort the list by Size, or look for a POST or PUT request. A request about as large as your file means the file was uploaded. If no request is that large, the work happened in your browser.

What it means for you

Sending files to a server is how most PDF sites work, and the large ones publish how long they keep files and how they protect them. It is not a scandal in itself.

But once a file is uploaded, you depend on that company's security, retention rules and country. For a contract, a payslip, an ID scan or a medical report, it is reasonable to prefer a tool that never receives the file.

A tool that works in the browser can be checked by anyone with the method above, in a minute.

Disclosure

This test is published by PDFDog, which makes browser-based PDF tools and so has an interest in the subject. The figures above are the raw measurements, so you can repeat the test and reach your own conclusion.

One PDFDog tool is an exception: PDF to Word sends the PDF over an encrypted connection to Adobe's PDF Services to convert it, and says so on its page. Every other PDFDog tool works in your browser.

Questions

Does iLovePDF upload my files?: In our test of its Compress PDF tool, yes: the whole file was sent to api32.ilovepdf.com as soon as it was chosen, before the Compress button was clicked.
Does Adobe Acrobat online upload my PDF?: Yes. In our test, the file was sent to unity-ew1.adobe.io before the page moved to acrobat.adobe.com, where it then appeared as a stored document.
How can I tell if a PDF website uploads my file?: Open the browser's developer tools (F12), go to the Network tab and choose a PDF. A request about as large as your file means it was uploaded; no such request means the work happened in your browser.
Is it safe to use online PDF tools for confidential documents?: Large services publish deletion and security policies, but an uploaded file depends on them. For sensitive documents, a tool that processes the file in your browser removes that risk.
Does PDFDog upload my files?: No, except for PDF to Word, which uses Adobe's PDF Services and says so on its page. Every other PDFDog tool works in your browser, which you can check with the method on this page.