Free Feature Flags & A/B Testing
Feature flag tools let you turn features on or off in your application without deploying new code. This allows you to release new features safely to a small group of users first, run experiments to see what works best, and quickly disable problematic features if something goes wrong. These platforms also support A/B testing so you can compare different versions and make decisions based on real user behavior. The free tiers are perfect for students, solo developers, open-source projects, and small teams. They help you reduce risk, gather feedback faster, and deliver better products by giving you more control over how and when new features reach your users. Every service listed here offers a genuine free tier that persists beyond a short trial, so you can shortlist practical options before you commit to a vendor.
Category directory
Compare free feature flags & a/b testing options
Review the services below, open the details sheet to inspect the free-tier limits, and then jump to the official site when you are ready to validate the latest plan terms.
Flagsmith
Flagsmith is an open-source feature flag and remote configuration service that works with almost every major programming language. You can control which users see which features, set up gradual rollouts, and change settings without redeploying your application. The platform offers both a free hosted tier and a fully open-source version that you can self-host for complete control. Developers like its clean interface and powerful targeting rules. It is suitable for personal projects, growing startups, and teams that want flexibility. Flagsmith helps you release features more confidently and experiment safely while keeping everything simple to manage.
Free tier snapshot
Generous free hosted tier available. Self-hosted open-source version is completely free with no usage limits
GrowthBook
GrowthBook is an open-source platform for feature flags and A/B testing. It includes built-in statistical analysis that helps you understand which variations perform better. You can create experiments, target specific user groups, and make data-driven decisions about your features. The free plan supports multiple users and allows unlimited flags and experiments. It works well with many popular frameworks and data sources. Developers and product teams use GrowthBook to test new designs, pricing changes, or functionality safely. Its transparent and self-hostable nature makes it a popular choice for teams that value openness and want full control over their experimentation platform.
Free tier snapshot
3 users, unlimited feature flags and experiments, basic A/B testing and analytics features on the free plan
Statsig
Statsig is a complete platform that combines feature management, A/B testing, analytics, and dynamic configuration in one place. It allows you to launch features gradually, run experiments, and measure their impact using real user data. The free tier offers unlimited team members, unlimited flags, and a good number of events per month. Developers appreciate its speed and detailed insights. It is especially useful for growing products that need strong experimentation capabilities. Statsig helps teams move faster while reducing the risk of releasing features that might negatively affect user experience. Its all-in-one approach saves time compared to using multiple separate tools.
Free tier snapshot
Unlimited seats and feature flags, unlimited experiments, up to 1 million events per month on the free plan
ConfigCat
ConfigCat is a developer-friendly feature flag service that focuses on simplicity and reliability. It supports unlimited team members on the free plan and provides SDKs for all popular programming languages. You can create targeting rules, schedule feature releases, and manage configuration changes easily. The free tier includes a reasonable number of flags, environments, and requests per month. Many developers choose ConfigCat because of its straightforward setup and strong focus on developer experience. It works well for both small personal projects and larger applications. ConfigCat helps teams release features safely and gather feedback without the complexity of managing their own infrastructure.
Free tier snapshot
10 feature flags, 2 environments, 5 million requests per month, and unlimited team members on the free plan
Always verify free tier limits directly on the provider's website before using in production — free tiers can change over time.