This page compares Vellum with the online PDF suites iLovePDF, Smallpdf, Adobe Acrobat online and PDF24. The difference is not quality but architecture: those services upload the file to their servers and delete it after a while, whereas Vellum runs the processing in the browser, on the device, with no transmission. The consequences: no account, no quota, no watermark, offline operation — verifiable by simply cutting the connection.
Vellum — free PDF tools whose processing stays on your device.