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SAT Specifications
This page has links to some important SAT specification documents which we use in creating FirmaSAT. We only use specification documents that are publicly available.
In particular, we use the .XSD files (that specify the structure of the XML documents) and the .XSLT files (that specify the construction of the "pipe string" (cadena original) used to compute the signature).
SAT do not provide any version control on their specification documents. You just have to know where to find them and then check if they have been changed. Of late (December 2021), SAT now seems to want to obscure the source of even the most important specification documents (we will add more on this subject later).
http://omawww.sat.gob.mx/tramitesyservicios/Paginas/complemento_carta_porte.htmand our comments on that.
Consulta los complementos y complementos concepto de facturaThere is a link Lista de complementos y complementos concepto at the bottom right-hand side under "Related Content" (Contenidos Relacionados). This links to a PDF file
MenuComplementos.pdf.
This link may not be up-to-date, but is still useful. Here is the most up-to-date archived copy dated 2023-11-29.
New 2021-12-26.
Rather than wade through the obscure links on the official SAT page above, use
our latest summary of
Complementos and Complementos Conceptowhich gives direct links to the SAT pages on each complemento and the underlying XSD specification files.
To contact us or comment on this page, please send us a message.
This page last updated 15 August 2025
