aicoolies logo
Flagsmith logo
Flagsmith logo

Flagsmith

Open-source feature flags and remote configuration

freemiumopen sourceupdated Apr 21, 2026

Flagsmith is an open-source feature flag and remote config platform with 15+ SDKs, a clean REST API, and simple Docker deployment. It supports boolean, multivariate, and string flags with segment-based targeting, A/B testing via flag variations, and environment-based workflows. Flagsmith provides a straightforward self-hosted alternative to LaunchDarkly with full API-first design under a BSD-3-Clause license.

Flagsmith takes the approach that feature flags should be simple to operate and deploy without requiring a platform engineering team to maintain. The core platform runs as a Django application with PostgreSQL, deployable via a single Docker Compose command. Its web dashboard provides a clean interface for creating flags, defining targeting segments based on user traits, and promoting flag configurations across development, staging, and production environments.

The platform supports multiple flag types including boolean toggles, multivariate flags with percentage-based allocation, and remote configuration values that can be changed without code deployments. Segment-based targeting allows defining user groups based on traits and applying different flag values per segment. Flag audit logs track every change with the responsible user and timestamp, providing compliance-ready feature management. The REST API enables full programmatic control for teams integrating flags into automated workflows.

With over 6,300 GitHub stars and nearly 6,000 commits across 477 releases, Flagsmith has earned its reputation as one of the most battle-tested open-source feature flag platforms. SDKs cover Python, JavaScript, React, Node.js, Java, .NET, Go, Ruby, PHP, Swift, Kotlin, Flutter, Rust, and Elixir. The BSD-3-Clause license ensures full freedom for self-hosted deployments, while the managed cloud option eliminates operational overhead for teams that prefer not to run their own infrastructure.

Pricing

Free self-hosted — cloud from $45/mo

full pricing breakdown →

Platforms

Docker, self-hosted — SDKs for 15+ languages

Categories

Tags

Use Cases

Related Tools

computed discovery: shared active categories · kept separate from editor-verified Alternatives

Cilium logo

Cilium

eBPF-based networking, security, and observability for Kubernetes

Cilium is a CNCF Graduated, Apache-2.0 project for Kubernetes networking, security, and observability using eBPF. It can replace kube-proxy, enforce identity-aware L3-L7 network policies, and add Hubble flow observability plus Tetragon runtime-security signals. Current source checks support GKE Dataplane V2 using Cilium/eBPF and Azure CNI Powered by Cilium for AKS.

Open Source
OrbStack logo

OrbStack

Fast and lightweight Docker Desktop alternative for macOS

OrbStack is a macOS application that replaces Docker Desktop with lightweight container and Linux VM management. Its docs emphasize fast starts, lower CPU and memory overhead, and native macOS integration with menu bar controls, file sharing, and network access to containers by name, with exact gains depending on workload. Supports Docker, Kubernetes, and full Linux VMs.

freemium
Ray logo

Ray

Distributed AI compute engine for scaling Python and ML workloads

Ray is an open-source distributed computing framework built for scaling AI and Python applications from a laptop to thousands of GPUs. It provides libraries for distributed training, hyperparameter tuning, model serving, reinforcement learning, and data processing under a single unified API. Ray's public site highlights OpenAI and other enterprise users. Maintained by Anyscale with Apache-2.0 open-source licensing.

Open Source
Act logo

Act

Run GitHub Actions locally for fast feedback

Act is an open-source tool that runs GitHub Actions workflows locally using Docker containers that match GitHub's execution environment. It provides instant feedback on workflow changes without pushing to a repository, supports matrix builds, secret management, and artifact handling. Act can also replace Makefiles by using workflow files as task definitions, making it useful for both CI/CD development and local task automation across development teams.

Open Source
Clerk logo

Clerk

Drop-in authentication for modern JavaScript apps

Clerk is a complete authentication and user management platform for React, Next.js, and modern JavaScript frameworks. It provides pre-built UI for sign-in, sign-up, user profiles, organizations, MFA, passkeys, JWT sessions, webhooks, and billing. The Hobby plan supports up to 50,000 monthly retained users per app, with Pro, Business, and Enterprise tiers for growing teams.

freemium
Docker logo

Docker

Build, share, and run containers

Industry-standard container platform for building, shipping, and running applications in isolated, reproducible environments. Package apps with all dependencies into portable containers using Dockerfiles and images. Docker Compose orchestrates multi-container applications. Docker Hub hosts millions of pre-built images. Docker Desktop provides GUI management on Mac/Windows. Essential for local development, CI/CD, and production deployments. The foundation of modern containerized infrastructure.

freemiumOpen SourceTelemetry

Used in Stacks

Comparisons

GrowthBook vs Flagsmith — Feature Flags with Experimentation vs Simple Feature Toggles

GrowthBook and Flagsmith are the two leading open-source feature flag platforms, but they target different needs. GrowthBook combines feature flags with a full experimentation and A/B testing engine, while Flagsmith focuses on straightforward feature management with simpler deployment. This comparison helps teams choose based on whether they need experimentation capabilities or just feature toggles.

GrowthBookFlagsmith

FAQ

What is Flagsmith?

Flagsmith is an open-source feature flag and remote config platform with 15+ SDKs, a clean REST API, and simple Docker deployment. It supports boolean, multivariate, and string flags with segment-based targeting, A/B testing via flag variations, and environment-based workflows. Flagsmith provides a straightforward self-hosted alternative to LaunchDarkly with full API-first design under a BSD-3-Clause license.

Is Flagsmith free?

Flagsmith offers a free tier alongside paid plans. Free self-hosted — cloud from $45/mo

Is Flagsmith open source?

Yes — Flagsmith is open source.

What are the best Flagsmith alternatives?

The top editor-verified Flagsmith alternatives are GrowthBook, Resolve AI.