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Connect to an external ClickHouse database

ClickHouse is a high-performance, column-oriented database system. It allows for fast ingestion of data and is optimized for analytical queries.

LangSmith uses ClickHouse as the primary data store for traces and feedback. By default, self-hosted LangSmith will use an internal ClickHouse database that is bundled with the LangSmith instance. This is run as a stateful set in the same Kubernetes cluster as the LangSmith application or as a Docker container on the same host as the LangSmith application.

However, you can configure LangSmith to use an external ClickHouse database for easier management and scaling. By configuring an external ClickHouse database, you can manage backups, scaling, and other operational tasks for your database. While Clickhouse is not yet a native service in Azure, AWS, or Google Cloud, you can run LangSmith with an external ClickHouse database in the following ways:


Using the first two options (LangSmith-managed ClickHouse or ClickHouse Cloud) will provision a Clickhouse service OUTSIDE of your VPC. However, both options support private endpoints, meaning that you can direct traffic to the ClickHouse service without exposing it to the public internet (eg via AWS PrivateLink, or GCP Private Service Connect).

Additionally, sensitive information can be configured to be not stored in Clickhouse. Please reach out to for more information.


  • A provisioned ClickHouse instance that your LangSmith application will have network access to (see above for options).
  • A user with admin access to the ClickHouse database. This user will be used to create the necessary tables, indexes, and views.
  • We only support standalone ClickHouse (not clustered or replicated) or ClickHouse Cloud.
  • We only support ClickHouse versions >= 23.9. Use of ClickHouse versions >= 24.2 requires LangSmith v0.6 or later. See the LangSmith release notes for more information.


You will need to provide several parameters to your LangSmith installation to configure an external ClickHouse database. These parameters include:

  • Host: The hostname or IP address of the ClickHouse database
  • HTTP Port: The port that the ClickHouse database listens on for HTTP connections
  • Native Port: The port that the ClickHouse database listens on for native connections
  • Database: The name of the ClickHouse database that LangSmith should use
  • Username: The username to use to connect to the ClickHouse database
  • Password: The password to use to connect to the ClickHouse database


With these parameters in hand, you can configure your LangSmith instance to use the provisioned ClickHouse database. You can do this by modifying the config.yaml file for your LangSmith Helm Chart installation or the .env file for your Docker installation.

enabled: true
host: "host"
port: "http port"
nativePort: "native port"
user: "default"
password: "password"
database: "default"
tls: false

Once configured, you should be able to reinstall your LangSmith instance. If everything is configured correctly, your LangSmith instance should now be using your external ClickHouse database.

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