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AIDevelopment

Frameworks for AI: why do you need them and which one to choose?

Compare LangChain, LlamaIndex and other frameworks, understand why they are needed, and choose the one that suits you!

К

Kodik

Author

2 min read

🤖 Why just GPT is not enough

  • Connect databases, PDF, API

  • Remember context

  • Manage agents (the model searches, writes code, and analyzes)

  • Build chains of actions

  • Use your data through vector repositories (RAG)

Without frameworks, you'll have to write all this manually. With frameworks, you just assemble the "constructor".

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🧩 What AI frameworks do

Opportunity

Why is it necessary?

RAG (access to external data)

Chat with PDF, websites, knowledge base

Agent approach

GPT itself decides what to do and in what order

Integrations (API, SQL, files)

GPT connects to real data

Caching, logging

For debugging and acceleration

Easy assembly of pipelines

Less code — faster result

🚀 Popular frameworks

LangChain is the most famous

🧱 Builder of everything: chains, agents, data processing, integrations. Supports OpenAI, Claude, Ollama, HuggingFace, and others.

Suitable if:

  • Need to build complex pipelines

  • You want to use different models and sources

  • Ready for a little more complexity for flexibility

LlamaIndex (ex-GPT Index)

📚 Specializes in RAG — connecting local documents, vector databases, working with texts.

Suitable if:

  • Need a "chat with PDF" or search your knowledge base

  • Want to quickly tweak semantic search?

  • You work with documents and files

Haystack

🔍 An open alternative for advanced search and chat tasks. Supports UI, connectors, pipelines.

Suitable if:

  • Do you want open-source and customization

  • Build a QA platform or chat on your data

  • You love Python and transparency

Semantic Kernel

🧠 From Microsoft. Focused on creating smart agents and skills that interact with each other.

Suitable if:

  • You are a .NET or TypeScript developer

  • Want a modular agent architecture

  • Integrate AI into an enterprise application

🔍 How to choose a framework?

Do you want...

Your choice

Quickly attach a chat with a PDF / knowledge base

LlamaIndex

Build a complex agent with logic and search

LangChain or Semantic Kernel

Maximum control and open-source

Haystack

Work with .NET and TS, enterprise solutions

Semantic Kernel

Minimum dependencies, only basic logic

Generally without a framework or simple llama.cpp + Python

💡 Tips from Kodik

  • Don't overcomplicate it. Often, an MVP can be made in pure Python with openai and chromadb.

  • Framework ≠ magic. These are just tools, without understanding the basics they will not help.

  • Better understand RAG and agentsthan chasing "new tools".

  • Look at the community — LangChain and LlamaIndex are actively developing.

In the attachment Code you will find courses in Python, JavaScript. Right in the code, with hints, exercises, and your own data!

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💬 Want a separate guide on LangChain, LlamaIndex or RAG? Write to us!

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