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Environment Variables

The LangGraph Server supports specific environment variables for configuring a deployment.

BG_JOB_ISOLATED_LOOPS

Set BG_JOB_ISOLATED_LOOPS to True to execute background runs in an isolated event loop separate from the serving API event loop.

This environment variable should be set to True if the implementation of a graph/node contains synchronous code. In this situation, the synchronous code will block the serving API event loop, which may cause the API to be unavailable. A symptom of an unavailable API is continuous application restarts due to failing health checks.

Defaults to False.

BG_JOB_TIMEOUT_SECS

The timeout of a background run can be increased. However, the infrastructure for a Cloud SaaS deployment enforces a 1 hour timeout limit for API requests. This means the connection between client and server will timeout after 1 hour. This is not configurable.

A background run can execute for longer than 1 hour, but a client must reconnect to the server (e.g. join stream via POST /threads/{thread_id}/runs/{run_id}/stream) to retrieve output from the run if the run is taking longer than 1 hour.

Defaults to 3600.

DD_API_KEY

Specify DD_API_KEY (your Datadog API Key) to automatically enable Datadog tracing for the deployment. Specify other DD_* environment variables to configure the tracing instrumentation.

If DD_API_KEY is specified, the application process is wrapped in the ddtrace-run command. Other DD_* environment variables (e.g. DD_SITE, DD_ENV, DD_SERVICE, DD_TRACE_ENABLED) are typically needed to properly configure the tracing instrumentation. See DD_* environment variables for more details.

LANGCHAIN_TRACING_SAMPLING_RATE

Sampling rate for traces sent to LangSmith. Valid values: Any float between 0 and 1.

See LangSmith documentation for more details.

LANGGRAPH_AUTH_TYPE

Type of authentication for the LangGraph Server deployment. Valid values: langsmith, noop.

For deployments to LangGraph Cloud, this environment variable is set automatically. For local development or deployments where authentication is handled externally (e.g. self-hosted), set this environment variable to noop.

LANGSMITH_RUNS_ENDPOINTS

For Bring Your Own Cloud (BYOC) deployments with self-hosted LangSmith only.

Set this environment variable to have a BYOC deployment send traces to a self-hosted LangSmith instance. The value of LANGSMITH_RUNS_ENDPOINTS is a JSON string: {"<SELF_HOSTED_LANGSMITH_HOSTNAME>":"<LANGSMITH_API_KEY>"}.

SELF_HOSTED_LANGSMITH_HOSTNAME is the hostname of the self-hosted LangSmith instance. It must be accessible to the BYOC deployment. LANGSMITH_API_KEY is a LangSmith API generated from the self-hosted LangSmith instance.

LANGSMITH_TRACING

Only for Self-Hosted Data Plane, Self-Hosted Control Plane, and Standalone Container

Disabling LangSmith tracing is only available for Self-Hosted Data Plane, Self-Hosted Control Plane, and Standalone Container deployments.

Set LANGSMITH_TRACING to false to disable tracing to LangSmith.

LOG_LEVEL

Configure log level. Defaults to INFO.

LOG_JSON

Set LOG_JSON to true to render all log messages as JSON objects using the configured JSONRenderer. This produces structured logs that can be easily parsed or ingested by log management systems. Defaults to false.

LOG_COLOR

This is mainly relevant in the context of using the dev server via the langgraph dev command. Set LOG_COLOR to true to enable ANSI-colored console output when using the default console renderer. Disabling color output by setting this variable to false produces monochrome logs. Defaults to true.

N_JOBS_PER_WORKER

Number of jobs per worker for the LangGraph Server task queue. Defaults to 10.

POSTGRES_URI_CUSTOM

Only for Self-Hosted Data Plane and Self-Hosted Control Plane

Custom Postgres instances are only available for Self-Hosted Data Plane and Self-Hosted Control Plane deployments.

Specify POSTGRES_URI_CUSTOM to use a custom Postgres instance. The value of POSTGRES_URI_CUSTOM must be a valid Postgres connection URI.

Postgres:

  • Version 15.8 or higher.
  • An initial database must be present and the connection URI must reference the database.

Control Plane Functionality:

  • If POSTGRES_URI_CUSTOM is specified, the LangGraph Control Plane will not provision a database for the server.
  • If POSTGRES_URI_CUSTOM is removed, the LangGraph Control Plane will not provision a database for the server and will not delete the externally managed Postgres instance.
  • If POSTGRES_URI_CUSTOM is removed, deployment of the revision will not succeed. Once POSTGRES_URI_CUSTOM is specified, it must always be set for the lifecycle of the deployment.
  • If the deployment is deleted, the LangGraph Control Plane will not delete the externally managed Postgres instance.
  • The value of POSTGRES_URI_CUSTOM can be updated. For example, a password in the URI can be updated.

Database Connectivity:

  • The custom Postgres instance must be accessible by the LangGraph Server. The user is responsible for ensuring connectivity.

REDIS_URI_CUSTOM

Only for Self-Hosted Data Plane and Self-Hosted Control Plane

Custom Redis instances are only available for Self-Hosted Data Plane and Self-Hosted Control Plane deployments.

Specify REDIS_URI_CUSTOM to use a custom Redis instance. The value of REDIS_URI_CUSTOM must be a valid Redis connection URI.

REDIS_KEY_PREFIX

Available in API Server version 0.1.9+

This environment variable is supported in API Server version 0.1.9 and above.

Specify a prefix for Redis keys. This allows multiple LangGraph Server instances to share the same Redis instance by using different key prefixes.

Defaults to ''.

REDIS_CLUSTER

Only Allowed in Self-Hosted Deployments

Redis Cluster mode is only available in Self-Hosted Deployment models, LangGraph Cloud SaaS will provision a redis instance for you by default.

Set REDIS_CLUSTER to True to enable Redis Cluster mode. When enabled, the system will connect to Redis using cluster mode. This is useful when connecting to a Redis Cluster deployment.

Defaults to False.