What is LangChain?

Relax. We'll talk through this in plain words — no textbook voice.

LangChain is a framework for building applications powered by Large Language Models (LLMs). It provides easy-to-use tools and abstractions for connecting LLMs to external data sources (PDFs, databases) and services (Google Search, APIs). LangChain is mainly used with Python and JavaScript.

python

# LangChain helps connect LLMs to other sources of data.
# This is a conceptual overview.
User -> [Prompt] -> LLM -> [Output]

# With LangChain:
User -> [Prompt Template] -> [LLM Chain] -> [LLM] -> [Output Parser] -> Formatted Output

You should see

(LangChain breaks the steps needed to work with an LLM into components, making them easy to wire together.)