This is a non-exhaustive list of websites that accept the digital certificate from Spanish Royal Mint (FNMT, from the Spanish Fábrica Nacional de Moneda y Timbre) as a method of authentication.
List of websites where Spanish FNMT Digital Certificate can be used for Authentication
Spanish Tax Agency
https://www2.agenciatributaria.gob.es
Spanish Tax Agency (Agencia Tributaria, in Spanish) has a web where you can authenticate using digital certificate.
For example, go to main page > Sede Electrónica > Mis Expendientes > Link “Acceda con certificado o DNI electrónico”, and digital certificate will be requested.
Madrid Town Hall
https://sede.madrid.es/portal/site/tramites/
Scroll down to “Mi carpeta” link, then choose “Continúe con DNIe/Certificado electrónico”.
Castile and León’s DELE Application
https://servicios.jcyl.es/dele/
Castile and León has created DELE application to allow to place publications on Spain’s legal deposit (depósito legal, in Spanish).
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