Are electronic signatures legal in Mexico?

What the Commercial Code says

Article 89 applies the e-commerce title throughout Mexico in commercial matters and sets its principles: technological neutrality, party autonomy, international compatibility, and the functional equivalence of a data message (mensaje de datos) to paper and of an electronic signature to a handwritten one. Article 89 bis adds that information can't be denied legal effect, validity or binding force just because it's in a data message.

• Written form is met by a data message if its information stays intact and accessible for later reference, whatever the format (art. 93).
• Signature is met if the data message can be attributed to the parties (art. 93), and an electronic signature appropriate for the purpose of the message satisfies a signature requirement (art. 97).
• Evidence. Data messages are recognized as evidence in commercial disputes (art. 1298-A).

Simple and advanced (fiable) signatures

The Code defines a firma electrónica as data in a data message, attached or logically associated by any technology, used to identify the signer and show that they approve the content. A firma electrónica avanzada o fiable must also meet the four tests in article 97: the signature creation data belong only to the signer; they were under the signer's sole control at signing; any later change to the signature is detectable; and any later change to the message is detectable. Anyone may still prove a signature's reliability, or unreliability, by other means.

The best-known advanced signature in Mexico is the e.firma, issued by the tax authority (SAT) and used for tax filings and government procedures; the SAT says it has the same legal effects as a handwritten signature. Private commercial contracts don't require it unless the parties or a specific law do.

Notarial acts and record keeping

Where a law requires an act to be granted in an instrument before a fedatario público, such as a notary handling a real estate transfer, article 93 lets the notary and the parties use data messages to state the exact terms they agree to. The notary then records how those messages were attributed to the parties, keeps a complete copy and grants the instrument under the law that governs it. The e-signature doesn't replace the notary.

Merchants must keep the originals of contracts and other documents that create rights and obligations for at least ten years, and for data messages that means keeping them intact and unaltered from when they were first finalized (art. 49), under an official Mexican standard (NOM) issued by the Ministry of Economy.

Where SignMaster fits

SignMaster provides a simple electronic signature for commercial paperwork: service contracts, quotes, supplier agreements and work orders. Signers can read the signing page in Spanish, and each signed PDF ends with a certificate of completion showing who signed, when and from which IP address, with a SHA-256 fingerprint that exposes any later change. It isn't an e.firma or an advanced signature, and it doesn't issue NOM conservation certificates.