feature-flags-service
A self-hosted, high-performance feature flag service built on .NET 10, designed as a cost-effective alternative to commercial solutions that can exceed £100 per month at scale. It delivers 50,000 requests per second with sub-5ms p99 latency and a 99.79 percent cache hit rate using FusionCache hybrid L1 memory and L2 Redis caching with eventual consistency guarantees. The service uses Clean Architecture principles, separating API, application, domain, and infrastructure layers for maintainability and scalability. Security is handled through API key authentication with hashed keys and project-scoped authorization. A typed .NET client SDK with optional caching, retry logic, and dependency injection support simplifies integration. A Blazor demo app showcases real-time flag updates via SignalR, propagating changes to the UI in under 100ms. The tech stack includes .NET 10 Minimal APIs, PostgreSQL, Redis with a backplane, Prometheus and Grafana for observability, and k6 for load testing. Performance is achieved thro