Open Source

Langfuse is open source for the following reasons:

• To establish complete transparency
• To enable the community to self-host and contribute (opens in a new tab)
• To collaborate on integrations with various other open-source tools and frameworks
• To assure users that Langfuse is open and does not impose lock-in, and that production traces are user data that can be exported/fetched at any time

Learn more about what's next for Langfuse on our roadmap.

License

Langfuse is licensed under an MIT license, with the exception of the /ee and /web/src/ee folders of the repository. These directories contain features that are commercially licensed. They are available on Langfuse Cloud and in the Enterprise Edition of Langfuse Self-Hosted. See License (opens in a new tab) for more details.

The Langfuse core product and all Langfuse-maintained integrations and SDKs are fully open-source and licensed under the MIT license.

Enterprise Edition (EE) FAQ

• What features are EE and what is MIT-licensed when self-hosting Langfuse? The core of Langfuse is MIT licensed and open-source (tracing, integrations, public API, prompt management). There are no restrictions on usage, modification or deployment of these features when self-hosting Langfuse. The EE features are commercially licensed add-on features that are not required for the core functionality of Langfuse (e.g., model-based evaluation, llm playground, SSO enforcement, etc.). The documentation and codebase are clearly marked ("Where is this feature available?") to indicate which features are MIT-licensed and which parts are EE (commercially licensed).
• Do I risk executing EE code when using Langfuse without a license? No, the EE features are only available when you have a license. You do not risk using EE features if you self-host Langfuse without a license, unless you modify the codebase to circumvent the checks.
• Do I need to care about the difference between MIT and EE when using Langfuse Cloud? No, depending on which tier of Langfuse Cloud you are on, you will have access to features that are both MIT and EE licensed.

Repositories

• Langfuse Server (UI and API): langfuse/langfuse (opens in a new tab)
• Langfuse Python SDK and integrations: langfuse/langfuse-python (opens in a new tab)
• JS SDK and integrations: langfuse/langfuse-js (opens in a new tab)
• Docs: langfuse/langfuse-docs (opens in a new tab)

Self-host vs Langfuse Cloud

The Langfuse team provides Langfuse Cloud as a managed solution to simplify the initial setup of Langfuse and to minimize the operational overhead of maintaining high availability in production. Get started for free on: https://cloud.langfuse.com (opens in a new tab).

Alternatively, Langfuse can be used locally and self-hosted.

Contributing

Here are the best ways to contribute to Langfuse via GitHub:

1. Submit and vote on Ideas.
2. Create and comment on Issues.
3. Create a pull request. See see Contributing.md (opens in a new tab) to get started.

Dependencies

Langfuse packages use open-source dependencies. Find a complete list in the configuration files across our repositories:

• Langfuse server: monorepo with multiple package.json files (opens in a new tab)
• Langfuse Python SDK: main pyproject.toml (opens in a new tab)
• Langfuse JS SDK: monorepo with multiple package.json files (opens in a new tab)

As the core Langfuse server is most actively developed, we run an automated license check (opens in a new tab) on every change to avoid adding dependencies with non-permissive licenses. If you find any issues, please let us know.