How to verify a Mexican contractor's RFC with the SAT, step by step

Go to sat.gob.mx, open Trámites del RFC and choose Valida en línea RFC´s uno a uno o de manera masiva hasta 5 mil registros.[2] The procedure page says the validator is for any individual or company that needs to confirm an RFC, runs online without authentication and returns whether the RFC is valid or invalid in the taxpayer registry.[1] Click Ejecutar en línea to open it.

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Type the characters in the image exactly, with upper- and lowercase letters; if you get them wrong, the page asks you to try again.[2] Then enter the RFC in RFC del contribuyente, with no spaces, and click Consultar RFC.[2] An individual’s RFC has 13 characters and a company’s 12, so a count is a quick first check.[3]

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Tick Validar RFC, nombre, denominación o razón social y CP to compare the RFC with the name and postal code on file.[2] For an individual, enter the name, first surname and second surname; for a company, its legal name without the company type, such as S.A. de C.V.; and the five-digit postal code of the tax address. Then click Consultar RFC.[2]

Ask the contractor for these details exactly as they appear on their tax registration, since the check compares them with what the SAT has on file.

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If the details match the registry, the validator confirms it; if they do not, the message names the field that does not match, such as the name or the postal code.[2] You can print the result or click Terminar to finish.[2] The bulk results use the same wording, so this table covers both:

The first five messages are the SAT’s result wording in its guide to the validator; the last is the error the guide warns about for RFCs typed with spaces.[2]

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To validate up to 5,000 RFCs in one go, prepare a plain-text file in UTF-8, with the pipe character (|) as separator and no header row. Each line holds a sequence number, the RFC without spaces, the name or legal name, and the postal code of the tax address.[2]

1|<RFC, 12 or 13 characters>|<name or legal name>|<5-digit postal code>
2|<RFC, 12 or 13 characters>|<name or legal name>|<5-digit postal code>

Click Validación masiva de RFC, select the file and click Validar. The validator returns a text file with the same four columns plus a fifth with the result for each line, in the wording of the table above.[2]

Because the RFC is the identity behind every invoice and tax form your contractor gives you. Mexico’s Federal Tax Code requires individuals and companies that file periodic tax returns or issue digital tax invoices to register in the Federal Taxpayer Registry and obtain an RFC.[3] It is also the number your contractor writes on line 6a of the W-8BEN, where the IRS asks for the foreign tax identifying number issued by the country where they are a tax resident.[4]

The SAT validator confirms two things in under a minute: that the RFC exists in the registry as a valid key, and, if you add the name and postal code, that it belongs to the person you contracted.[2] A typo in the RFC, a name that does not match or an unregistered key is far cheaper to catch before the first payment than after a year of invoices.

An individual’s RFC has 13 characters: four letters taken from the name, six digits for the date of birth and a three-character check code called the homoclave. A company’s RFC has 12: three letters, six digits for the date of incorporation and the homoclave.[3]

The two generic keys are worth knowing. The SAT uses XEXX010101000 for transactions with residents abroad, such as your company, and the validator reports both generic RFCs as invalid by design.[2] Always check the contractor’s own RFC, never the generic one.

The procedure page sits on the SAT portal, but the validator itself runs on a separate SAT server, and in our test from outside Mexico on November 2, 2026 it did not respond. If that happens, ask the contractor or your accountant in Mexico to run the check and send you the result: the validator has a print option for exactly that.[2] File the printout with the contractor’s W-8BEN and agreement.

No. The validator answers one question, whether the RFC is valid or invalid in the taxpayer registry, plus the name and postal code match if you ask for it.[1] It does not tell you whether the contractor files their returns, and it says nothing about whether the relationship is really independent work rather than employment, which Mexican labor law decides on the facts of how the work is done. Treat the RFC check as identity verification: necessary before the first payment, not a substitute for a sound contract.