LangChain

LangChain Tutorial

LangChain is an open-source framework that helps developers build applications powered by large language models (LLMs). Instead of just sending prompts to a model, LangChain lets you chain prompts together, connect external data sources, and build intelligent agents. It’s one of the most popular ecosystems for AI app development.

Make Money With This 💰

• Build custom AI chatbots or assistants for businesses using LangChain.

• Sell hosted AI apps by combining LangChain + Pinecone or Weaviate (affiliate).

• Offer freelance LangChain development services on Upwork/Fiverr.

• Create niche SaaS products (e.g. AI research tools, customer support bots).

• Teach LangChain courses/tutorials and monetise via Gumroad or YouTube.

Use Cases

• Customer Support Bots → connected to company knowledge bases.

• Research Assistants → search, summarise, and cite across documents.

• AI Agents → autonomous workflows for scheduling, emails, or trading.

• Knowledge Management → integrate LLMs with Notion, Google Drive, etc.

Key Features

• Prompt Chaining → link multiple prompts into workflows.

• Agents → LLMs that can decide which tools to call.

• Memory → applications that remember past interactions.

• Integrations → APIs, vector databases, cloud hosting.

• Open Source → growing library of templates and modules.

Getting Started

Step 1: Install Python on your computer.

Step 2: Run in terminal: pip install langchain

Step 3: Get an API key from a model provider (e.g. OpenAI, Anthropic, Hugging Face).

Step 4: Start with a simple chain: input prompt → LLM response.

Step 5: Extend with tools: connect to APIs, vector databases, or document loaders.

Example Prompt

Type (Python):

from langchain.llms import OpenAI

from langchain.llms import OpenAI

from langchain.chains import SimpleChain

llm = OpenAI()

chain = SimpleChain(llm, prompt="Translate this English text to French: 'How are you today?'")

print(chain.run())

What you’ll see: “Comment allez-vous aujourd’hui ?”

Tool Snapshot: Pros & Cautions

Best if: you’re a developer or startup building custom AI products.

Not ideal if: you’re a non-technical user (it requires coding knowledge).

Pricing Snapshot

• Free → open source.

• Costs depend on the LLM + hosting infra you choose:

  • OpenAI API: ~$0.002 per 1K tokens.

  • Pinecone: ~$0–$50/month for vector DB.

  • Weaviate: SaaS hosting available.

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