Build a Simple LLM Application with LCEL

install LangChain


pip instal langchain

LangSmith

Install python-dotenv and create .env


pip install python-dotenv
touch .env

write the following code to file .env


LANGCHAIN_TRACING_V2="true"
LANGCHAIN_API_KEY="..."

auto import env in code


from dotenv import load_dotenv
load_dotenv()  # take environment variables from .env.
# Upon code is all you need

Export env in shell or global env


export LANGCHAIN_TRACING_V2="true"
export LANGCHAIN_API_KEY="..."