Best agent framework (2026)

How we rank: output quality on real builder tasks (40%) · fit for the use case (25%) · pricing & free-tier value (15%) · openness / lock-in (10%) · momentum & maintenance (10%). Editorial judgment, not lab benchmarks; paid placement never changes order. Methodology
  1. LangGraph Open source
    Graph-based control for agents that need reliability and state.
  2. OpenAI Agents SDK Open source
    Lightweight official SDK; minimal abstractions.
  3. Mastra Open source
    TypeScript-first agent framework; good fit for JS builders.
  4. Pydantic AI Open source
    Type-safe Python agents from the Pydantic team.
  5. CrewAI Open source
    Role-based multi-agent crews; quick to start.
  6. LlamaIndex Open source
    Best known for data/RAG pipelines over your documents.

Other rankings: Best AI coding agent · Best AI code editor · Best free / open-source coding agent · Best vibe coding app builder · Best AI for game dev assets