Flagsmith

Flagsmith is an open-source feature flag and remote configuration platform that helps development teams manage feature rollouts, toggle features on and off, and configure their applications remotely — across web, mobile and server-side environments. Feature flags are an essential modern development practice, letting teams ship code safely by controlling which features are active for which users, decoupling deployment from release, and enabling gradual rollouts, testing and instant rollbacks. Flagsmith provides this capability in a flexible, open and self-hostable package.

The platform lets you create and manage feature flags and remote config values, control them per environment and per user segment, and roll features out gradually or target them to specific groups — all from a central dashboard, with SDKs for many languages and platforms so you can use flags wherever your code runs. This means teams can release features confidently, experiment with A/B tests, manage configuration without redeploying, and quickly disable problematic features if needed. Being open source, Flagsmith can be self-hosted for full control over data and infrastructure, which is important for organizations with privacy, security or compliance requirements, while a managed cloud option offers convenience.

Flagsmith is used by development and product teams that want a reliable, flexible feature flag system and value the control and transparency of open source. By enabling safer releases, gradual rollouts, experimentation and remote configuration, it helps teams ship faster and with less risk, which is increasingly important as deployment frequency rises. Its open, self-hostable nature appeals especially to teams that want to own their feature management infrastructure and avoid lock-in. As feature flags become a standard part of modern software delivery, robust, flexible platforms to manage them are essential. For development teams that want an open-source, self-hostable feature flag and remote config platform to manage rollouts across their applications, Flagsmith offers a capable, flexible and well-regarded solution.