8 Use Cases of LangChain

September 3, 2024
30 min read

Summarize with ChatGPT

AI applications are transforming how businesses handle complex data challenges, yet many organizations struggle to move beyond basic chatbot implementations. Despite the explosive growth in AI adoption, data teams often find themselves rebuilding similar functionality across projects while missing opportunities to leverage advanced capabilities like multi-agent orchestration and real-time data processing. LangChain has emerged as the leading framework for building sophisticated AI applications, offering a comprehensive ecosystem that transforms how developers approach everything from document analysis to complex data integration workflows.

This article explores the most impactful LangChain use cases, from foundational applications like summarization and chatbots to cutting-edge implementations including multi-agent systems and real-time data processing. You'll discover practical implementations, learn advanced techniques, and understand how to build production-ready AI applications that solve real business problems.


Before You Begin: Make Your Data Accessible

Before exploring LangChain use cases, make sure your data is easy to access. It often lives in multiple sources, making it hard to use for training. No-code data-movement platforms like Airbyte can streamline data integration.

Airbyte

Airbyte offers 600+ pre-built data connectors plus:

  • GenAI workflows with RAG-specific transformations and automated indexing capabilities
  • Connector Development Kit (CDK) to create custom connectors in minutes with enhanced security features
  • PyAirbyte, a Python library for extracting, transforming, and loading data programmatically with native LangChain integration

Below is a quick example that uses PyAirbyte to read a CSV file from Google Drive and convert it into a list of LangChain-ready Document objects. (Replace the placeholders with your own values.)

%pip install --quiet airbyte

import airbyte as ab

service_json = ab.get_secret('service_json')

source = ab.get_source(
    "source-google-drive",
    install_if_missing=True,
    config={
        "folder_url": "https://drive.google.com/drive/folders/xxxxxxxxxxxxxxxx",
        "credentials": {
            "auth_type": "Service",
            "service_account_info": f"""{service_json}""",
        },
        "streams": [{
            "name": "NFLX",
            "globs": ["**/*.csv"],
            "format": {"filetype": "csv"},
            "validation_policy": "Emit Record",
            "days_to_sync_if_history_is_full": 3
        }]
    },
)

source.check()                         # verify connection

source.select_all_streams()
read_result = source.read()

documents_list = []
for key, value in read_result.items():
    docs = value.to_documents()
    documents_list.extend(docs)

print(documents_list[0])               # inspect one row

You can now chunk these documents, embed them, and load them into a vector database for RAG pipelines. The integration supports incremental updates and automatic deduplication, reducing embedding costs while maintaining data freshness. (See this full tutorial.)


How Can You Use LangChain for Document Summarization?

LangChain Summarization Use Case

Summarization helps you condense content such as articles, chat logs, legal documents, and research papers. Because LLMs have context-length limits, larger texts must be split into chunks and then summarized with approaches like stuff (put everything in one prompt) or map-reduce. Modern implementations leverage advanced chunking strategies and context optimization techniques to improve accuracy while reducing token usage.

Prerequisites

%pip install --upgrade --quiet langchain-openai langchain python-dotenv

from dotenv import load_dotenv
import os
load_dotenv()
openai_api_key = os.getenv('OPENAI_API_KEY', 'YOUR_API_KEY')

Summarizing Short Text

from langchain_openai import OpenAI
from langchain.prompts import PromptTemplate
from langchain.chains import LLMChain

llm = OpenAI(
    temperature=0,
    model_name='gpt-3.5-turbo-instruct',
    openai_api_key=openai_api_key
)

template = """
%INSTRUCTIONS:
Please summarize the following piece of text.
Respond in a manner that a 5-year-old would understand.
Focus on the main ideas and key points.

%TEXT:
{text}
"""

prompt = PromptTemplate(input_variables=["text"], template=template)
chain = LLMChain(llm=llm, prompt=prompt)

confusing_text = """
For the next 130 years, debate raged over the fundamental nature of light...
"""

result = chain.run(text=confusing_text)
print(result)

Summarizing Longer Text with Advanced Techniques

from langchain.chains.summarize import load_summarize_chain
from langchain.text_splitter import RecursiveCharacterTextSplitter
from langchain.schema import Document

# Load text content
with open('data/PaulGrahamEssays/good.txt') as f:
    text = f.read()

# Advanced text splitting with semantic awareness
text_splitter = RecursiveCharacterTextSplitter(
    separators=["\n\n", "\n", ".", "!", "?"],
    chunk_size=4000,
    chunk_overlap=200,
    length_function=len
)
docs = text_splitter.create_documents([text])

# Use map-reduce chain for better handling of long documents
chain = load_summarize_chain(
    llm, 
    chain_type='map_reduce',
    verbose=True,
    map_prompt=PromptTemplate.from_template(
        "Summarize the following text, focusing on key insights:\n\n{text}"
    ),
    combine_prompt=PromptTemplate.from_template(
        "Combine these summaries into a comprehensive overview:\n\n{text}"
    )
)

summary = chain.run(docs)
print(summary)

Context-Aware Summarization

Advanced summarization implementations use custom prompt templates that adapt to document types and include metadata for better context understanding. This approach reduces hallucination while maintaining accuracy across different content formats.


How Do You Build Conversational Agents with LangChain?

LangChain makes it easy to build conversational agents that incorporate memory and context persistence. Modern chatbot implementations leverage streaming responses, conversation memory, and multi-turn dialogue management for more natural interactions.

Basic Chatbot with Memory

```python
from langchain_openai import OpenAI
from langchain.chains import ConversationChain
from langchain.memory import ConversationBufferMemory
from langchain.prompts import PromptTemplate

template = """
You are a helpful assistant that provides clear, accurate information.
Your responses should be conversational and engaging.

Current conversation:
{history}

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