Fathom Layer ranking
Best Agent Frameworks (2026)
Ranked by our design score and documented from primary-source specs — not affiliate payouts. 5 entries, reviewed by a human, updated as the field moves. See how we score.
- 1
Devin
The first fully autonomous AI software engineer capable of planning and executing complex code workflows.
Full review & specs → - 2
LangChain
Open Source
The most popular and versatile orchestration framework for LLMs.
Full review & specs → - 3
SmolAgents
Open Source
Lightweight HuggingFace agents that focus on raw Python code generation.
Full review & specs → - 4
Mastra
Open Source
Opinionated, strongly-typed agent framework for Next.js and TypeScript.
Full review & specs → - 5
Pydantic AI
Agent framework built on Pydantic's validation model, for Python systems that must audit every output.
Full review & specs →
Looking for the full field? Browse every agent frameworks in the index.