Last updated Repo data refreshed 25 Oct 20262 options
Our pick · flagsmith
Our pick for a startup SaaS is Flagsmith: it is BSD-3-Clause licensed, self-hosts on PostgreSQL, and has a free cloud plan for up to 50,000 requests a month if you would rather not run it yourself. Unleash is the better fit when flags must be evaluated inside your own apps: its SDKs evaluate flags locally, and it lists more than 25 SDKs. Unleash's hosted version is a paid Enterprise plan.
★ 6,616 starsLicence: BSD-3-ClauseLast commit 24 Oct 2026Latest release 20 Oct 2026Python
A modern, open-source feature flag and remote config platform designed for easy deployment and scalability across various applications.
Best for: SaaS startups seeking a modern, full-featured, and cloud-native friendly feature flag and remote config solution that is easy to deploy and scale.
What's good
Provides both feature flags and remote configuration capabilities within a single, intuitive platform.
Features a clean, modern UI/UX and well-documented API, making it easy to get started and manage flags.
Supports self-hosted deployment with Docker, Kubernetes, or via their cloud service, offering deployment flexibility.
Excellent support for local evaluation, robust client-side SDKs, and handling of offline scenarios.
Watch out for
Requires a separate database (Postgres, SQL Server, or MySQL) and Redis for self-hosting, adding some infrastructure complexity.
While feature-rich, some of the most advanced enterprise-level features might be reserved for their commercial offering.
Community support is active but might not be as extensive as older, larger projects like Unleash.
★ 13,901 starsLicence: AGPL-3.0Last commit 23 Oct 2026Latest release 22 Oct 2026TypeScript
A feature management platform offering robust feature toggles, A/B testing, and rollout strategies, built for performance and scalability.
Best for: SaaS startups needing a powerful, scalable, and feature-rich feature flag system that can grow with complex rollout strategies and permission management demands.
What's good
Offers a comprehensive suite of enterprise-grade features, including advanced rollout strategies (e.g., gradual, sticky, release environments).
Mature and production-proven, used by many large companies, ensuring reliability and stability.
Extensive language SDKs for both server-side and client-side integration, making it versatile across different tech stacks.
Good performance with real-time flag updates and efficient client-side evaluation.
Watch out for
Can be overly complex and feature-rich for startups with very simple feature flagging needs, potentially introducing unnecessary overhead.
Requires a dedicated PostgreSQL database, adding an external dependency and infrastructure management for self-hosting.
The UI, while functional, might feel less modern compared to newer, more design-focused alternatives.
"Dormant" means no commit pushed to the default branch in the last 12 months. "Archived" means the maintainers have marked the repository read-only on GitHub. "Deprecated" means the project's README says it is deprecated or no longer maintained. Stars, licence, commit and release dates come from the GitHub API (GitLab for projects developed there) and are cached for up to 24 hours. The written analysis is AI-assisted and checked against that data.
Self-hosting
Both run on PostgreSQL when you host them yourself: Flagsmith's own Docker Compose file sets it up with a PostgreSQL database, and Unleash's getting-started guide runs a PostgreSQL container alongside Unleash.
Flagsmith is licensed BSD-3-Clause and Unleash AGPL-3.0, according to their licence files on GitHub. Flagsmith has a free cloud plan for up to 50,000 requests a month and one team member. Unleash's hosted version is Unleash Enterprise, a paid plan with a 14-day trial.
Unleash lists more than 25 SDKs, and flags are evaluated inside the SDKs or Unleash Edge rather than on the Unleash server. Flagsmith documents its SDKs and an OpenFeature integration in its integration overview.
GrowthBook combines feature flags with experiments: its free Starter plan includes unlimited feature flags and unlimited experiments for up to 3 users. If you want to measure the effect of a release, not just control it, see feature flag tools compared and A/B testing tools compared.
Flagsmith and Unleash are active: each has had a commit in the last 12 months (most recent: Flagsmith on 24 Oct 2026, Unleash on 23 Oct 2026). Status is checked against GitHub daily.
What licences do Flagsmith and Unleash use?
Flagsmith: BSD-3-Clause; Unleash: AGPL-3.0. Check each project's licence file before use.
