How Scout24 Is Building Next-Generation Real Estate Search with AI

Scout24, Germany's largest real estate platform, is building HeyImmo, an intelligent real estate expert assistant that goes beyond simple search functionality to guide users. Moving away from traditional search methods, it aims to serve as a 'sparring partner' role that converses with users to recommend suitable listings and summarize information.

HeyImmo runs on GPT-5 and provides various response formats depending on user needs, including summaries, bullet points, and listing lists with image previews. Technically, instead of a complex multi-agent framework, the team adopted a simplified architecture leveraging function calling and focused components to ensure speed and reliability.

For quality control, they built their own evaluation model inspired by the OpenAI Evals framework, and conducted 'swarm testing' involving all employees to check edge cases. They also worked closely with OpenAI solution architects to improve the quality and safety of responses.

Going forward, Scout24 plans to expand this assistant feature to all stakeholders on the platform, including buyers, landlords, homeowners, and agents, to strengthen network effects.