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Self-Hosted Open Source DevOps Python Feature Flags A/B Testing Remote Config

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Last Updated: 09-07-2026
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Flagsmith

With over 6,400 GitHub stars, 130 contributors, and 512 releases, Flagsmith is the open-source feature flag and remote configuration platform that gives development teams granular control over feature releases, remote configuration values, user segmentation, and A/B testing from a single self-hosted dashboard. Feature flags support boolean toggles and remote config values simultaneously — every flag carries both an enabled state and a configurable value, letting teams deploy functional and visual changes without code modifications or app store approvals. User segments target audiences by attributes, percentage rollouts, and custom rules, enabling beta testing, canary releases, and gradual feature rollouts with real-time toggle control. Multivariate flags split traffic across multiple variations with configurable percentage weights for A/B and multivariate testing with analytics integration. The flag evaluation engine runs server-side with local evaluation mode in SDKs for sub-millisecond performance without network calls, supporting 15+ languages including TypeScript, Python, Java, C#/.NET, Go, Ruby, PHP, Swift, Kotlin, Flutter, React, and Next.js. The REST API and webhooks enable integration with CI/CD pipelines, and pre-built connectors exist for Datadog, New Relic, Amplitude, Mixpanel, Segment, Heap, Rudderstack, and Slack. Built on Django with a React frontend, self-hosting deploys via Docker Compose with PostgreSQL, or via Helm charts and the OpenShift Operator for Kubernetes environments. Change history provides a complete audit trail of flag modifications. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. BSD-3-Clause licensed.

Flagsmith
Flagsmith
Flagsmith
Flagsmith
Flagsmith

Benefits

  • Feature Flags with Remote Config
  • Every feature flag carries both an enabled state and a configurable value, enabling boolean toggles and remote configuration changes without code deployments or app store submissions.
  • User Segmentation and Targeting
  • Target users by attributes, percentage rollouts, and custom rules for beta testing, canary releases, and gradual feature rollouts with real-time toggle control from the dashboard.
  • 15+ SDK Languages Supported
  • Client and server SDKs cover TypeScript, Python, Java, C#/.NET, Go, Ruby, PHP, Swift, Kotlin, Flutter, React, and Next.js with local evaluation for sub-millisecond flag checks.
  • Self-Hosted with BSD-3-Clause License
  • Core feature flags, remote config, segmentation, and multivariate testing are fully open source under the permissive BSD-3-Clause license with Docker Compose and Helm deployment options.

Features

  • Multivariate Flag Testing
  • Split traffic across multiple variations with configurable percentage weights for A/B and multivariate testing with built-in analytics integration support.
  • Analytics Integrations
  • Pre-built connectors for Datadog, New Relic, Amplitude, Mixpanel, Segment, Heap, Rudderstack, and Slack surface flag evaluation data in existing analytics pipelines.
  • Server-Side Local Evaluation
  • SDKs evaluate flags locally from a cached environment document for sub-millisecond performance without network calls, reducing latency in high-throughput applications.
  • REST API and Webhooks
  • The REST API enables programmatic flag management for CI/CD pipeline integration, while webhooks trigger external workflows on flag state changes in real time.
  • Change History Audit Trail
  • Complete audit log tracks every flag modification with timestamps, user attribution, and previous values for compliance, debugging, and rollback investigations.