Flagsmith vs. Unleash: Which Open Source Feature Flag Tool Wins?
Published: 2023-11-15 08:58:16

## Introduction

[Unleash](https://github.com/Unleash/unleash) and [Flagsmith](https://github.com/flagsmith/flagsmith) are two popular platforms for [feature management](https://www.featbit.co/blogs/Free-and-Open-Source-Feature-Flag-Tools). They allow developers to deploy, test, and optimize features without affecting the end users. In this blog post, we will compare them in terms of tech stack, features, integrations, pricing, support community, and open source license.

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/wp3rxr43le5rwjum9dh2.png)

**Tech stack**: Unleash is built with Node.js and PostgreSQL, while Flagsmith is built with Python and PostgreSQL. Both platforms use Redis for caching and message queueing. Unleash and Flagsmith have both a web interface written in React.

**Features**: Both platforms offer similar features, such as [feature flags](https://www.featbit.co/), [feature toggles](https://www.featbit.co/blogs/Free-and-Open-Source-Feature-Flag-Tools), feature experiments, multivariate testing, segmentation, targeting, and feedback. However, Unleash has some unique features, such as gradual rollout, kill switch, activation strategies, custom strategies, and plugins. Flagsmith has some unique features, such as identity management, user traits, remote config, environments, and organizations.

**Integrations**: Both platforms support various integrations with third-party tools and services. Unleash integrates with Slack, Datadog, Prometheus, Sentry, and more. Flagsmith integrates with Segment, Amplitude, Mixpanel, Optimizely, and more.

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/tr7eim85v1hmm9ejq8nn.png)

**Pricing**: Both platforms offer free and paid plans. Unleash has a free plan for up to 10 users and 1000 feature flags. Its paid plans start from $49 per month for up to 25 users and 2500 feature flags. Flagsmith has a free plan for up to 50 users and unlimited feature flags. Its paid plans start from $99 per month for up to 500 users and unlimited feature flags.

**Support community**: Both platforms have active support communities on GitHub, Slack, Discord, Stack Overflow, and other channels. Unleash has over 9000 stars on GitHub and over 1900 members on Slack. Flagsmith has over 3000 stars on GitHub and over 500 members on Discord.

**Open source license**: Both platforms are open source and have permissive licenses. Unleash is licensed under the Apache License 2.0, while Flagsmith is licensed under the BSD 3-Clause License.


If you're not the fun of Javascript and Python, you can try other [feature flag tools](https://www.featbit.co/blogs/Free-and-Open-Source-Feature-Flag-Tools) which is built with Golang, C# and .NET

## FeatBit

[FeatBit](https://www.featbit.co) provides an enterprise-level feature flag service. It's completely open source and licensed under the MIT license. It's basically built with .NET and MongoDB (support Azure CosmosDB, PostgreSQL with FerretDB), and uses Redis for caching and message queuing. FeatBit has a web interface written in Angular.

FeatBit also offers a professional version that adds Kafka for message queuing and ClickHouse for data warehousing. This provides a robust solution for companies that have high traffic (like more than millions MAU) and need to do data analysis.

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/fwr78jaul13ms2qcpd9u.png)

FeatBit provides a more flexible way to do traffic splitting for ab test, such as mutually exclusive and orthogonal layering features to solve overlapping problems. FeatBit currently also provides a basic frequentist analysis tool for ab test.

FeatBit supports various integrations with third party tools and services. Like Flagsmith and Unleash, FeatBit also offers OpenFeature SDKs to avoid vendor lock-in.

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/4j1wvjizul0x1qvsro3e.png)

FeatBit offers more free open source features than Flagsmith and Unleash. It now offers a self-hosting solution with unlimited seats for enterprise-level customers. FeatBit has active support communities on GitHub and Slack.


## Go Feature Flag Tools

[GoFeatureFlag](https://github.com/thomaspoignant/go-feature-flag) is a lightweight and fast feature flag service for Go applications. It's fully open source and licensed under the Apache License 2.0. It's built with Go and uses a pluggable storage system that supports various backends, such as Consul, Redis, YAML file, etc. GoFeatureFlag has a simple and intuitive API that makes it easy to use in any Go project. GoFeatureFlag is a more performant and lightweight solution than LaunchDarkly and ConfigCat. It does not require any external dependencies or services, and can run entirely within your own infrastructure. GoFeatureFlag has active development and maintenance on GitHub.

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/jnx2kc2dyqfp5tzegclb.png)

[Flipt](https://github.com/flipt-io/flipt) is a self-hosted feature flag solution that helps you deliver faster and safer software. It's completely open source and licensed under the Apache 2.0 license. It's built with Go and uses SQLite, PostgreSQL, or MySQL as the backend database. Flipt has a web interface written in React. Flipt also has a cloud version that offers more features and benefits for teams that want to scale up their feature flag management. This includes advanced analytics, team collaboration, and security features.


## Others

If you're interested in learning more feature flag tools, you can check out the following resources:

- [Self-Hosted and Open Source Feature Flag tools](https://www.featbit.co/blogs/Free-and-Open-Source-Feature-Flag-Tools)
- [All-in-one suite of product and data tools](https://posthog.com/blog/best-open-source-feature-flag-tools)
- [GitHub Feature Flag Repositories](https://github.com/search?q=feature+flag&type=repositories)

## Conclusion

Which open source feature flag tool will win in 2023? Unleash, Flagsmith, FeatBit (and others) can all be the winners, it depends on which tech stack, pricing and features you need. So, you can choose the best one for your project.


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Original article: https://www.featbit.co/blogs/flagsmith-vs-unleash