La Poderosa: firma con e.firma

Sign contracts and PDF documents with your e.firma (the digital certificate issued by Mexico's tax authority, SAT), in the order you choose, and verify any signed document by its folio. HOW IT WORKS • Upload a PDF (or share it to La Poderosa from WhatsApp, Mail or Files) and invite the signers by email. • Each signer gets their own link, reviews the document and signs with their e.firma. Your private key and password never leave your device: only your certificate (which is public) and the signature travel to the server. • Keep your e.firma on your phone protected with Face ID or fingerprint, and sign next time without hunting for files. • Every signature gets a third-party timestamp. When everyone has signed, the document is sealed and anyone can verify it by folio at lapoderosa.app. LEGAL VALUE The signature applied is an advanced electronic signature backed by a valid SAT certificate. Between private parties it has the effects recognized by Mexico's Commercial Code, articles 89 to 97. La Poderosa does not issue certificates, does not act as a notary and does not provide a certified date. TRY IT WITHOUT YOUR E.FIRMA Mark a request as a test and sign it with the demo e.firma: the document is labeled as having no legal validity, but you see the whole flow. Signers invited by link do not need an account. No passwords: you sign in with a link sent to your email. La Poderosa is a service of Riviera Media Digital, S.A. de C.V.