Cloudflare built a managed service for parsing and storing DMARC reports using their platform's features. This was made possible by leveraging Cloudflare Workers and Durable Objects, as well as other tools like R2 storage buckets and the PostalMime library. The system is designed to handle large volumes of data while maintaining performance and scalability. Additionally, an open-source version of a worker for processing DMARC reports was released by Cloudflare to aid developers in building similar services.