# Locally Hosted Setup This page contains instructions for installing and then setting up the environment to use the locally hosted version of tracing. ## Installation 1. Ensure you have Docker installed (see [Get Docker](https://docs.docker.com/get-docker/)) and that it’s running. 2. Install the latest version of `langchain`: `pip install langchain` or `pip install langchain -U` to upgrade your existing version. 3. Run `langchain-server` 1. This will spin up the server in the terminal. 2. Once you see the terminal output `langchain-langchain-frontend-1 | ➜ Local: [http://localhost:4173/](http://localhost:4173/)`, navigate to [http://localhost:4173/](http://localhost:4173/) 4. You should see a page with your tracing sessions. See the overview page for a walkthrough of the UI. 5. Currently, trace data is not guaranteed to be persisted between runs of `langchain-server`. If you want to persist your data, you can mount a volume to the Docker container. See the [Docker docs](https://docs.docker.com/storage/volumes/) for more info. 6. To stop the server, press `Ctrl+C` in the terminal where you ran `langchain-server`. ## Environment Setup After installation, you must now set up your environment to use tracing. This can be done by setting an environment variable in your terminal by running `export LANGCHAIN_HANDLER=langchain`. You can also do this by adding the below snippet to the top of every script. **IMPORTANT:** this must go at the VERY TOP of your script, before you import anything from `langchain`. ```python import os os.environ["LANGCHAIN_HANDLER"] = "langchain" ```