High-quality German contact data is defined by several benchmarks: accuracy (95%+ deliverability), compliance (full GDPR/DSGVO consent records), recency (updated within the last 3-6 months), and completeness. For phone data, this includes correct dialing codes and mobile vs. landline identification. Source transparency is critical—data should be traceable to its origin and collection ... https://www.b2cdatabase.co/germany-phone-number-list/