Case Study: HolidayCheck achieves €2,500/day cost savings and authenticates millions of monthly users with Auth0

HolidayCheck Saves €2,500 Per Day Using Auth0 Authentication

HolidayCheck is a leading German travel portal with about 13 million monthly visits, over 9.4 million reviews, coverage of 900,000+ hotels and more than 10 million holiday photos. Because the site relies on user-generated content, building trust and protecting customer data are critical; HolidayCheck’s growing number of platforms and features made their in‑house authentication costly and hard to maintain, and they needed a GDPR‑compliant, reliable identity solution.

HolidayCheck adopted Auth0 for centralized, standards‑based authentication across web, mobile and machine clients, simplifying integrations (e.g., Sign In with Apple), speeding feature development and improving security. The company estimates Auth0 replaces a five‑ to six‑person development effort and delivers roughly €2,500 in daily savings while providing consistent, low‑friction login and stronger user trust.

HolidayCheck

Björn Zapadlo

Director of Technology