PAC compliance

In Mexico no CFDI is valid without going through a PAC. The PAC validates that the XML complies with SAT schemas, adds a digital fiscal stamp (TFD) that includes SAT’s cryptographic seal, records it in its system, and returns it to the issuer. There are about a dozen authorized PACs; they charge per stamp (between $0.10 and $1 USD depending on volume). An ERP operating in Mexico picks a PAC, integrates against its API, handles vendor-specific errors (monthly quotas, rejected formats, delays), and should be able to switch PACs with zero code change. cifraHQ Enterprise abstracts the PAC integration behind a uniform interface: if your current PAC goes down, we pivot to a backup without the user noticing.