Sede electrónica (online office / e-government portal)

The tax agency's portal is sede.agenciatributaria.gob.es.

A freelancer or small company uses several portals during the year: the tax agency's to file forms, check tax data and download certificates; the social security portal to register, deregister and change contribution brackets; and sometimes the portal of the regional government or the town hall. Companies are required to deal with the tax agency electronically, so their notifications arrive only through this channel.

The typical mistake is never logging in to check notifications. An electronic notification is treated as received if you do not open it within the period set by law, and the deadlines to respond start running anyway. Another common slip is letting your digital certificate expire right before a deadline: renewing it in good time avoids scares. If you work with an advisor, you can grant them a power of representation so they can act on your behalf without sharing your credentials.

The sede electrónica is linked to the digital certificate, to paying by domiciliación bancaria and to every form, such as the census declaration or the quarterly VAT return. In kontora you prepare forms casilla by casilla with deadline reminders and file them from the app itself with your digital certificate (303, 130, 111, 115 and 123 by direct filing; 349, 347, 190, 180 and 193 through TGVI); the rest you file yourself on the portal.

Guides that use this term

• Choosing accounting software as an autónomo in Spain: Verifactu, the free AEAT app and eight criteria to get it right
• I missed a Hacienda deadline: what to do now
• Verifactu postponed: when it comes into force in 2027, which law sets the dates and what to do in the meantime
• Deferring or splitting a tax payment to Hacienda in Spain: how to apply, what can be deferred and what it costs
• Spanish tax calendar 2026-2027 for autónomos and SL companies

Related terms

• Casilla: A casilla is one of the numbered fields on a Spanish tax form or return where a specific figure or piece of data goes.
• Domiciliación bancaria: Domiciliación bancaria is the authorization you give to a body or company to collect a payment directly from your bank account on a recurring basis.
• Cl@ve: Cl@ve is the electronic identification system used by Spanish public administrations, allowing access to online procedures without needing a digital certificate.

Full glossary