Vellum analyzes a PDF that no longer opens or shows an error, then rebuilds its internal cross-reference table to produce a valid file again. Recoverable content — text and images — is preserved as far as possible during the operation. The repair happens entirely in your browser, without sending the damaged document to a server.
It analyzes the file and rebuilds its internal cross-reference table — the structure a PDF reader uses to locate pages and objects — to produce a valid file again. Recoverable content, text and images, is preserved as far as possible.
No. Some PDFs are damaged beyond any automatic repair: if the missing data is truly destroyed, no tool, including Vellum, can invent it from nothing.
No, the repair happens entirely in your browser, without sending the document to a server, and the service is free.
Vellum — free PDF tools whose processing stays on your device.