The Buzón Tributario (Tax Mailbox) is the official communication system between the SAT and taxpayers in Mexico. It functions as a mandatory digital channel through which the SAT sends notifications, requirements, and messages of interest, and where taxpayers can submit requests and queries. Its activation is mandatory, and failure to do so can result in significant fines.
What Is the Tax Mailbox?
The Tax Mailbox is a digital platform created by the SAT that functions as an official messaging system between the tax authority and taxpayers. It was established in the Federal Tax Code and its use is mandatory for all individuals and legal entities registered in the RFC.
Unlike conventional email, notifications received through the Tax Mailbox have legal validity and produce legal effects. This means that if the SAT sends you a requirement through this channel, it is considered legally notified even if you haven't read it.
What Is It Used For?
The Tax Mailbox has multiple functions:
Receiving official notifications: Information requirements, invitations to regularize situations, audit actions.Receiving SAT notices: Legislative changes, administrative facilities, important deadlines.Article 69-B notifications: If your company is presumably listed as EFOS or EDOS, the notification arrives through this channel.Submitting requests: Applications, clarifications, and appeals before the tax authority.Consulting fiscal information: Status of procedures, refund status, tax credits.Receiving payment proposals: The SAT can send personalized tax regularization proposals.How to Activate the Tax Mailbox
Requirements:
Active RFCValid e.firma or SAT PasswordEmail address and cell phone number to receive alertsProcess:
Go to sat.gob.mxNavigate to "Buzón Tributario"Log in with your RFC and e.firma or passwordRegister at least one email address and one cell phone numberConfirm the contact methods with the verification codes you'll receiveThe Mailbox will be activated and you'll receive alerts when you have new messagesMandatory Status and Penalties
Tax Mailbox activation has been mandatory since 2020. Consequences of not activating it include:
Fines of $3,850 to $11,540 MXN for not enabling the mailboxFines of $1,400 to $4,200 MXN for not registering or keeping contact methods updatedService by posting: If you don't have an active mailbox, the SAT can notify you by posting (publication at their facilities), which reduces your time and defense capacityImpact on [Tax Compliance Opinion](/blog/opinion-cumplimiento-sat): Not having an active mailbox can affect your tax compliance opinionDeadlines for Responding to Notifications
When you receive a notification in the Tax Mailbox:
You have 3 business days to open the message from when it was sentIf you don't open it, it is considered notified on the fourth business dayDeadlines to respond or challenge begin from the notification dateIt is essential to check the mailbox frequently to avoid missing legal deadlinesSecurity Recommendations
Check your mailbox frequently — at least once a weekKeep updated your email address and cell phone numberDon't ignore alerts you receive by email or SMSKeep evidence of received notifications and your responsesEnable push notifications if you use the SAT Mobile appImportance in the Business Context
The Tax Mailbox is relevant for compliance analysis because:
A company with an active mailbox demonstrates a minimum level of fiscal formalityUnattended notifications can lead to tax debts that affect the Tax Compliance OpinionIgnored requirements can escalate to more severe audit actionsLack of an active mailbox may indicate a company that is not current with its obligationsAt CRiskCo, we verify the comprehensive compliance of evaluated companies, including indicators derived from their interaction with the SAT. Our platform automates the query of multiple fiscal sources to provide a complete risk and compliance picture.
Want to automate fiscal compliance verification for your counterparties? [Explore our compliance solutions](/solutions/compliance).