The best LLM & Agent Frameworks
Every option ranked — open-source, self-hostable, and commercial — by our transparent Sovereignty Score, with honest trade-offs so you choose what fits you, not us.
The orchestration layer of an AI app — frameworks (or deliberately none) for chaining model calls, retrieval, tools, and agents. A decision every AI builder revisits as models get more capable.
L4Models & tooling — layer 4 of the AI stack- 1
Direct SDKs (no framework)
Top pickOpen sourceThe 2026 consensus: official SDKs + a few hundred lines you own.
Free — you pay only your model provider; no framework tier, no per-seat tooling · in our LangChain comparison →
What is Direct SDKs (no framework)? →93sovereignty - 2
LlamaIndex
Open sourceThe focused RAG framework — data in, grounded answers out.
Free (MIT); optional hosted LlamaCloud for managed parsing/extraction · in our LangChain comparison →
What is LlamaIndex? →90sovereignty - 3
Haystack
Open sourceThe production-pipeline veteran — explicit, modular, Apache-2.0.
Free (Apache-2.0); deepset offers a commercial platform on top · in our LangChain comparison →
What is Haystack? →89sovereignty - 4
DSPy
Open sourceProgramming, not prompting — Stanford's optimizer-driven approach.
Free (MIT) · in our LangChain comparison →
What is DSPy? →88sovereignty - 5
Microsoft Agent Framework
Open sourceSemantic Kernel + AutoGen, unified — the enterprise agent stack.
Free (MIT); integrates naturally (but not exclusively) with Azure services · in our LangChain comparison →
What is Microsoft Agent Framework? →80sovereignty
Is it free?
The free tier, its real limits and where you start paying — read from each vendor's own pricing page and dated.
Run these yourself
What each one actually needs — real RAM, honest running cost, and the setup time nobody quotes.
- Self-hosting LlamaIndex 4 GB for the app; your vector store is the real cost
- Self-hosting Haystack 4 GB
Replacing a specific tool?
Head-to-head comparisons for each popular llm & agent frameworks product.
Straight head-to-heads
Two llm & agent frameworks tools, side by side — verified facts and a plain verdict.