eSignature law in Mexico

Electronic signatures are legally binding in Mexico under the Commercial Code and standard NOM-151, with the advanced e.firma (FIEL) carrying the strongest legal weight.

Governing law: Código de Comercio (Title II, Electronic Commerce) + NOM-151-SCFI-2016 + Ley de Firma Electrónica Avanzada (2003)

Mexico recognises electronic signatures principally through the 2003 electronic-commerce reforms to the Código de Comercio, which give a data message the same legal standing as a paper document and provide that a signature requirement is satisfied by a reliable electronic method attributable to the signer. The Código distinguishes a simple electronic signature (firma electrónica) from an advanced one (firma electrónica avanzada or FIEL/e.firma), the latter issued by the tax authority (SAT) or an accredited Prestador de Servicios de Certificación and carrying a presumption of integrity and authorship. NOM-151-SCFI-2016 sets the standard for preserving data messages and constancias de conservación. The Ley de Firma Electrónica Avanzada governs use of the advanced signature with the federal public administration.

What makes an eSignature valid in Mexico

• Attribution of the signature to the signer
• Reliability of the method for the purpose for which the message was generated
• Integrity and availability of the data message for later reference
• Consent to transact by electronic means
• For the strongest presumption: an advanced signature (e.firma) plus NOM-151 preservation

Where eSignatures are not valid

• Acts requiring a public deed before a notary (e.g. real-estate transfers, incorporations)
• Certain family-law and succession instruments
• Documents that specific statutes reserve to a formal or physical form
• Some filings that public bodies require to use the e.firma

FAQ

Are electronic signatures legal in Mexico?

Yes. Under the Código de Comercio a reliable electronic signature attributable to the signer has the same legal effect as a handwritten one, and the advanced e.firma carries a presumption of authorship and integrity.

What is the e.firma (FIEL) in Mexico?

The e.firma is Mexico's advanced electronic signature, issued by the tax authority (SAT). It carries the strongest legal presumption and is required for many dealings with public bodies; private contracts do not require it.

Can I sign a business contract electronically in Mexico?

Yes. Commercial contracts and agreements between private parties are valid with electronic signatures under the Código de Comercio, provided the method is reliable and attributable.