Self-Hosting Langfuse - Open Source LLM Observability

Langfuse Server, which includes the API and Web UI, is open-source and can be self-hosted using Docker.

For a detailed component and architecture diagram, refer to CONTRIBUTING.md.

Prerequisites: Postgres Database

Langfuse requires a persistent Postgres database to store its state. You can use a managed service on AWS, Azure, or GCP, or host it yourself. Once the database is ready, keep the connection string handy. At least version 12 is required.

Deploying the Application

Deploy the application container to your infrastructure. You can use managed services like AWS ECS, Azure Container Instances, or GCP Cloud Run, or host it yourself.

During the container startup, all database migrations will be applied automatically. This can be optionally disabled via environment variables.

docker pull langfuse/langfuse:2

docker pull langfuse/langfuse:latest

docker run --name langfuse \
-e DATABASE_URL=postgresql://hello \
-e NEXTAUTH_URL=http://localhost:3000 \
-e NEXTAUTH_SECRET=mysecret \
-e SALT=mysalt \
-e ENCRYPTION_KEY=0000000000000000000000000000000000000000000000000000000000000000 \ # generate via: openssl rand -hex 32
-p 3000:3000 \
-a STDOUT \
langfuse/langfuse

Recommended Instance Size

For production environments, we suggest using a configuration of 2 CPU cores and 3 GB of RAM for the Langfuse container. On AWS, this would equate to a t3.medium instance. The container is stateless, allowing you to autoscale it based on actual resource usage.

Configuring Environment Variables

Langfuse can be configured using environment variables (.env.prod.example). Some are mandatory as defined in the table below:

Authentication

Email/Password

Email/password authentication is enabled by default. Users can sign up and log in using their email and password.

To disable email/password authentication, set AUTH_DISABLE_USERNAME_PASSWORD=true. In this case, you need to set up SSO instead.

If you want to provision a default user for your Langfuse instance, you can use the LANGFUSE_INIT_* environment variables.

Password Reset

• If transactional emails are configured on your instance via the SMTP_CONNECTION_URL and EMAIL_FROM_ADDRESS environments, users can reset their password by using the “Forgot password” link on the login page.

• If transactional emails are not set up, passwords can be reset by following these steps:

  1. Update the email associated with your user account in database, such as by adding a prefix.
  2. You can then sign up again with a new password.
  3. Reassign any organizations you were associated with via the organization_memberships table in database.
  4. Finally, remove the old user account from the users table in database.

SSO

To enable OAuth/SSO provider sign-in for Langfuse, add the following environment variables:

Use *_ALLOW_ACCOUNT_LINKING to allow merging accounts with the same email address. This is useful when users sign in with different providers or email/password but have the same email address. You need to be careful with this setting as it can lead to security issues if the emails are not verified.

Need another provider? Langfuse uses Auth.js, which integrates with many providers. Add a feature request on GitHub if you want us to add support for a specific provider.

Additional configuration

Headless Initialization

By default, you need to create a user account, organization and project via the Langfuse UI before being able to use the API. You can find the API keys in the project settings within the UI.

If you want to automatically initialize these resources, you can optionally use the following LANGFUSE_INIT_* environment variables. When these variables are set, Langfuse will automatically create the specified resources on startup if they don’t already exist. This allows for easy integration with infrastructure-as-code and automated deployment pipelines.

The different resources depend on each other in the following way. You can e.g. intialize an organization and a user wihtout having to also initialize a project and API keys, but you cannot initialize a project without also initializing an organization.

Organization
├── Project      (part of organization)
│   └── API Keys (set for project)
└── User         (owner of organization)

Troubleshooting:

• If you use LANGFUSE_INIT_* in Docker Compose, do not double-quote the values (GitHub issue).
• The resources depend on one another (see note above). For example, you must create an organization to initialize a project.

Configuring the Enterprise Edition

The Enterprise Edition (compare versions) of Langfuse includes additional optional configuration options that can be set via environment variables.

Health and Readiness Check Endpoint

Langfuse includes a health check endpoint at /api/public/health and a readiness check endpoint at /api/public/ready. The health check endpoint checks both API functionality and database connectivity and indicates if the application is alive. The readiness check endpoint indicates if the application is ready to serve traffic.

Access the health and readiness check endpoints:

curl http://localhost:3000/api/public/health
curl http://localhost:3000/api/public/ready

The potential responses from the health check endpoint are:

• 200 OK: Both the API is functioning normally and a successful connection to the database was made.
• 503 Service Unavailable: Either the API is not functioning or it couldn’t establish a connection to the database.

The potential responses from the readiness check endpoint are:

• 200 OK: The application is ready to serve traffic.
• 500 Internal Server Error: The application received a SIGTERM or SIGINT and should not receive traffic.

Applications and monitoring services can call this endpoint periodically for health updates.

HTTPS

For encryption in transit, HTTPS is strongly recommended. Langfuse itself does not handle HTTPS directly. Instead, HTTPS is typically managed at the infrastructure level. There are two main approaches to handle HTTPS for Langfuse:

1. Load Balancer Termination: In this approach, HTTPS is terminated at the load balancer level. The load balancer handles the SSL/TLS certificates and encryption, then forwards the decrypted traffic to the Langfuse container over HTTP. This is a common and straightforward method, especially in cloud environments.

   • Pros: Simplifies certificate management as it is usually a fully managed service (e.g. AWS ALB), offloads encryption overhead from application servers.
   • Cons: Traffic between load balancer and Langfuse container is unencrypted (though typically within a secure network).

2. Service Mesh Sidecar: This method involves using a service mesh like Istio or Linkerd. A sidecar proxy is deployed alongside each Langfuse container, handling all network traffic including HTTPS.

   • Pros: Provides end-to-end encryption (mutual TLS), offers advanced traffic management and observability.
   • Cons: Adds complexity to the deployment, requires understanding of service mesh concepts.

Once HTTPS is enabled, you can configure add LANGFUSE_CSP_ENFORCE_HTTPS=true to ensure browser only allow HTTPS connections when using Langfuse.

Build Langfuse from source

While we recommend using the prebuilt docker image, you can also build the image yourself from source.

The repo includes multiple Dockerfile files. You only need to build the web Dockerfile as shown below.

# clone repo
git clone https://github.com/langfuse/langfuse.git
cd langfuse
 
# checkout production branch
# main branch includes unreleased changes that might be unstable
git checkout production
 
# build image
docker build -t langfuse/langfuse -f ./web/Dockerfile .

Custom Base Path

If you want to deploy Langfuse behind a custom base path (e.g. https://yourdomain.com/langfuse), you can set the NEXT_PUBLIC_BASE_PATH environment variable. This is useful if you want to deploy Langfuse on a subpath, especially when integrating Langfuse into existing infrastructure.

As this base path is inlined in static assets, you cannot use the prebuilt docker image. You need to build the image from source with the NEXT_PUBLIC_BASE_PATH environment variable set at build time.

When using a custom base path, NEXTAUTH_URL must be set to the full URL including the base path and /api/auth. For example, if you are deploying Langfuse at https://yourdomain.com/langfuse-base-path, you need to set:

NEXT_PUBLIC_BASE_PATH="/langfuse-base-path"
NEXTAUTH_URL="https://yourdomain.com/langfuse-base-path/api/auth"

Build image with NEXT_PUBLIC_BASE_PATH as build argument:

# clone repo
git clone https://github.com/langfuse/langfuse.git
cd langfuse
 
# use production branch
# main branch includes unreleased changes that might be unstable
git checkout production
 
# build image with NEXT_PUBLIC_BASE_PATH
docker build -t langfuse/langfuse --build-arg NEXT_PUBLIC_BASE_PATH=/langfuse-base-path -f ./web/Dockerfile .

Troubleshooting

If you encounter issues, ensure the following:

• NEXTAUTH_URL exactly matches the URL you’re accessing Langfuse with. Pay attention to the protocol (http vs https) and the port (e.g., 3000 if you do not expose Langfuse on port 80).
• Set HOSTNAME to 0.0.0.0 if you cannot access Langfuse.
• SSO: Ensure that the OAuth provider is configured correctly. The return path needs to match the NEXTAUTH_URL, and the OAuth client needs to be configured with the correct callback URL.
• Encode special characters in DATABASE_URL, see this StackOverflow answer for details.
• If you use the SDKs to connect with Langfuse, use auth_check() to verify that the connection works.
• Make sure you are at least on Postgres 12.
• When using Docker Compose / Kubernetes, your application needs to connect to the Langfuse container at the docker internal network address that you specified, e.g. http://langfuse:3000/http://langfuse.docker.internal:3000. Learn more: docker compose networking documentation, kubernetes networking documentation

Updating the Application

To update the application:

1. Stop the container.
2. Pull the latest container.
3. Restart the application.

During container startup, any necessary database migrations will be applied automatically if the database schema has changed. This can be optionally disabled via environment variables.

Langfuse is released through tagged semver releases. Check GitHub releases for information about the changes in each version.

(Optional) Apply newly supported models to existing data in Langfuse

Langfuse includes a list of supported models for usage and cost tracking. If a Langfuse update includes support for new models, these will only be applied to newly ingested traces/generations.

Optionally, you can apply the new model definitions to existing data using the following steps. During the migration, the database remains available (non-blocking).

1. Clone the repository and create an .env file:

   # Clone the Langfuse repository
   git clone https://github.com/langfuse/langfuse.git
    
   # Navigate to the Langfuse directory
   cd langfuse
    
   # Install all dependencies
   pnpm i
    
   # Create an .env file
   cp .env.dev.example .env

2. Edit the .env to connect to your database from your machine:

   .env

   NODE_ENV=production
    
   # Replace with your database connection string
   DATABASE_URL=postgresql://postgres:postgres@localhost:5432/postgres

3. Execute the migration. Depending on the size of your database, this might take a while.

   pnpm run models:migrate

4. Clean up: remove the .env file to avoid connecting to the production database from your local machine.

Kubernetes deployments

Kubernetes is a popular choice for deploying Langfuse when teams maintain the rest of their infrastructure using Kubernetes. You can find community-maintained templates and Helm Charts in the langfuse/langfuse-k8s repository.

If you encounter any bugs or have suggestions for improvements, please contribute to the repository by submitting issues or pull requests.

Platform-specific information

Support

If you experience any issues, please join us on Discord or contact the maintainers at support@langfuse.com.

For support with production deployments, the Langfuse team provides dedicated enterprise support. To learn more, reach out to enterprise@langfuse.com or schedule a demo.

Alternatively, you may consider using Langfuse Cloud, which is a fully managed version of Langfuse. You can find information about its security and privacy here.

FAQ

• Are prebuilt ARM images available?
• Are older versions of the SDK compatible with newer versions of Langfuse?
• I cannot connect to my docker deployment, what should I do?
• I have forgotten my password
• How can I restrict access on my self-hosted instance to internal users?
• How to manage different environments in Langfuse?
• Can I deploy multiple instances of Langfuse behind a load balancer?
• What kind of telemetry does Langfuse collect?

GitHub Discussions