Feature Flagging

GrowthBook is an open-source feature flagging, A/B testing, and product analytics platform. It helps teams safely release features, run experiments, and measure results. Free tier: 3 users, 1 project, unlimited flags and experiments, 1M events/month, 1M CDN requests/month, and 5GB bandwidth. No credit card required. Self-hosted version supports unlimited users and API requests.

Statsig is a product development platform offering feature flags, A/B testing, experimentation, product analytics, and session replay. Free tier: 2 million events/month, unlimited feature flag checks and seats, 50,000 session replays/month, and 1-year analytics retention. No credit card required. Exceeding the event limit disables metric-lift calculations, but feature flags continue working.

Amplitude is an analytics platform designed to help businesses understand user behavior and optimize digital products. It offers features like user segmentation, cohort analysis, and real-time event tracking, enabling data-driven decision-making. Amplitude's interface and data visualization tools allow teams to identify trends, measure user engagement, and improve product experiences.

Optimizely is a digital experience platform that enables businesses to experiment, personalize, and optimize their digital products and experiences. It provides tools for A/B testing, content management, feature flagging, and customer data management.