Network measurement conducted on 29 August 2026 from Switzerland. The same synthetic test PDF was dropped into the compression tool of several online PDF services, in a browser instrumented to log every outgoing request. Results: iLovePDF uploads the file to api110.ilovepdf.com (OVH, Germany) on drop, before any click; PDF2Go to www12.pdf2go.com (Hetzner, Nuremberg), with a simultaneous request to Microsoft Clarity; PDF24 to filetools14.pdf24.org (Hetzner, Nuremberg) despite the “Secure” badge displayed. Smallpdf could not be measured with this method and no conclusion is drawn. Vellum, on the same test, issues no network request at all: processing runs on the device. The deletion these services advertise happens after transmission, not instead of it.
Vellum — free PDF tools whose processing stays on your device.