Environment Variables¶

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

BG_JOB_ISOLATED_LOOPS¶

SetBG_JOB_ISOLATED_LOOPS toTrue to execute background runs in an isolated event loop separate from the serving API event loop.

This environment variable should be set toTrue 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 toFalse.

BG_JOB_SHUTDOWN_GRACE_PERIOD_SECS¶

Specifies, in seconds, how long the server will wait for background jobs to finish after the queue receives a shutdown signal. After this period, the server will force termination. Defaults to180 seconds. Set this to ensure jobs have enough time to complete cleanly during shutdown. Added inlanggraph-api==0.2.16.

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 viaPOST /threads/{thread_id}/runs/{run_id}/stream) to retrieve output from the run if the run is taking longer than 1 hour.

Defaults to3600.

DD_API_KEY¶

SpecifyDD_API_KEY (yourDatadog API Key) to automatically enable Datadog tracing for the deployment. Specify otherDD_* environment variables to configure the tracing instrumentation.

IfDD_API_KEY is specified, the application process is wrapped in theddtrace-run command. OtherDD_* environment variables (e.g.DD_SITE,DD_ENV,DD_SERVICE,DD_TRACE_ENABLED) are typically needed to properly configure the tracing instrumentation. SeeDD_* environment variables for more details.

LANGCHAIN_TRACING_SAMPLING_RATE¶

Sampling rate for traces sent to LangSmith. Valid values: Any float between0 and1.

SeeLangSmith documentation for more details.

LANGGRAPH_AUTH_TYPE¶

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

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

LANGGRAPH_POSTGRES_POOL_MAX_SIZE¶

Beginning with langgraph-api version0.2.12, the maximum size of the Postgres connection pool (per replica) can be controlled using theLANGGRAPH_POSTGRES_POOL_MAX_SIZE environment variable. By setting this variable, you can determine the upper bound on the number of simultaneous connections the server will establish with the Postgres database.

For example, if a deployment is scaled up to 10 replicas andLANGGRAPH_POSTGRES_POOL_MAX_SIZE is configured to150, then up to1500 connections to Postgres can be established. This is particularly useful for deployments where database resources are limited (or more available) or where you need to tune connection behavior for performance or scaling reasons.

Defaults to150 connections.

LANGSMITH_RUNS_ENDPOINTS¶

For deployments withself-hosted LangSmith only.

Set this environment variable to have a deployment send traces to a self-hosted LangSmith instance. The value ofLANGSMITH_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 deployment.LANGSMITH_API_KEY is a LangSmith API generated from the self-hosted LangSmith instance.

LANGSMITH_TRACING¶

SetLANGSMITH_TRACING tofalse to disable tracing to LangSmith.

Defaults totrue.

LOG_COLOR¶

This is mainly relevant in the context of using the dev server via thelanggraph dev command. SetLOG_COLOR totrue to enable ANSI-colored console output when using the default console renderer. Disabling color output by setting this variable tofalse produces monochrome logs. Defaults totrue.

LOG_LEVEL¶

Configurelog level. Defaults toINFO.

LOG_JSON¶

SetLOG_JSON totrue to render all log messages as JSON objects using the configuredJSONRenderer. This produces structured logs that can be easily parsed or ingested by log management systems. Defaults tofalse.

MOUNT_PREFIX¶

SetMOUNT_PREFIX to serve the LangGraph Server under a specific path prefix. This is useful for deployments where the server is behind a reverse proxy or load balancer that requires a specific path prefix.

For example, if the server is to be served underhttps://example.com/langgraph, setMOUNT_PREFIX to/langgraph.

N_JOBS_PER_WORKER¶

Number of jobs per worker for the LangGraph Server task queue. Defaults to10.

POSTGRES_URI_CUSTOM¶

SpecifyPOSTGRES_URI_CUSTOM to use a custom Postgres instance. The value ofPOSTGRES_URI_CUSTOM must be a validPostgres 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:

• IfPOSTGRES_URI_CUSTOM is specified, the LangGraph Control Plane will not provision a database for the server.
• IfPOSTGRES_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.
• IfPOSTGRES_URI_CUSTOM is removed, deployment of the revision will not succeed. OncePOSTGRES_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 ofPOSTGRES_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_CLUSTER¶

SetREDIS_CLUSTER toTrue 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 toFalse.

REDIS_KEY_PREFIX¶

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_URI_CUSTOM¶

SpecifyREDIS_URI_CUSTOM to use a custom Redis instance. The value ofREDIS_URI_CUSTOM must be a validRedis connection URI.

RESUMABLE_STREAM_TTL_SECONDS¶

Time-to-live in seconds for resumable stream data in Redis.

When a run is created and the output is streamed, the stream can be configured to be resumable (e.g.stream_resumable=True). If a stream is resumable, output from the stream is temporarily stored in Redis. The TTL for this data can be configured by settingRESUMABLE_STREAM_TTL_SECONDS.

See thePython andJS/TS SDKs for more details on how to implement resumable streams.

Defaults to120 seconds.