This repository demonstrates four different chain types available in LangChain, showing how they can be used to build powerful, composable AI workflows.
- Simple Chain
- Sequential Chain
- Parallel Chain
- Conditional Chain
A Simple Chain passes input through a single sequence of operations.
Advantages
- Easy to implement
- Minimal configuration
- Ideal for small, focused tasks
Use Case
- Taking a question and returning a concise answer
- Summarizing a short text snippet
A Sequential Chain runs multiple chains one after another, passing the output of one chain as the input to the next.
Advantages
- Clear control over execution order
- Good for multi-step reasoning
- Easy to debug
Use Case
- First summarizing a document, then translating it
- Generating an outline, then expanding it into a full draft
A Parallel Chain runs multiple chains at the same time using the same input, then aggregates their outputs.
Advantages
- Faster execution for independent tasks
- Can handle multiple perspectives or processing methods in parallel
Use Case
- Getting answers from multiple LLM prompts for comparison
- Running classification and sentiment analysis simultaneously
A Conditional Chain decides which chain to run based on input conditions.
Advantages
- Flexible, dynamic behavior
- Saves computation by avoiding unnecessary steps
Use Case
- Routing a user query to either a summarizer or a translator based on query type
- Detecting language and choosing the appropriate processing chain