Markus Keller

DACH Tech Reviewer & Connectivity Analyst · Cellesim DACH

Based in the tech hub of Berlin, Markus Keller is the Lead Tech Reviewer for Cellesim’s DACH market. Known for his uncompromising 'Preis-Leistung' (price-performance) analyses, Markus rigorously compares global eSIM providers like Airalo and Holafly against local giants like Telekom and Vodafone. A strong advocate for data privacy (GDPR), he exposes hidden roaming traps and helps German-speaking travelers find the most secure and reliable connectivity worldwide.