Best free Google Agent Development Kit (ADK) alternatives

✦ WhyA Google Agent Development Kit (ADK) alternative — Build stateful, multi-agent apps as graphs.

• Build stateful, multi-agent apps as graphs
• Human-in-the-loop and durable execution
• Works with any LLM
• Open-source with a hosted platform

✦ WhyA Google Agent Development Kit (ADK) alternative — Lightweight agent orchestration from OpenAI.

• Lightweight agent orchestration from OpenAI
• Agent handoffs, guardrails and tracing
• Tool and function calling built in
• Open-source, pay only for model usage

✦ WhyA Google Agent Development Kit (ADK) alternative — Multi-agent conversation framework.

• Multi-agent conversation framework
• Event-driven, async agent design
• Studio UI for prototyping
• Fully open-source

✦ WhyA Google Agent Development Kit (ADK) alternative — Type-safe Python agent framework from the Pydantic team, validated structured outputs.

• Type-safe Python agent framework from the Pydantic team, validated structured outputs
• Model-agnostic (OpenAI, Anthropic, Gemini, Groq, Mistral, local)
• Built-in dependency injection and streaming; pairs with Pydantic Logfire for observability

✦ WhyA Google Agent Development Kit (ADK) alternative — Open-source TypeScript framework (Apache 2.0) for agents, workflows and RAG.

• Open-source TypeScript framework (Apache 2.0) for agents, workflows and RAG
• Drops directly into existing React/Next.js apps or runs standalone
• Built-in workflow engine with suspend/resume and human-in-the-loop steps

✦ WhyA Google Agent Development Kit (ADK) alternative — Open-source (Apache-2.0) Python framework, 41.7k GitHub stars.

• Open-source (Apache-2.0) Python framework, 41.7k GitHub stars
• AgentOS: FastAPI-based production runtime for deploying agents
• Control-plane UI for monitoring live agent systems across clouds

✦ WhyA Google Agent Development Kit (ADK) alternative — Extremely minimal open-source library (~1,000 lines) from Hugging Face.

• Extremely minimal open-source library (~1,000 lines) from Hugging Face
• CodeAgent paradigm: agents write actions as executable code, not JSON
• Model-agnostic and modality-agnostic (text, vision, audio) with sandboxed execution via E2B/Docker/Modal

✦ WhyA Google Agent Development Kit (ADK) alternative — Open-source (6,800+ stars) Python and TypeScript SDK from AWS.

• Open-source (6,800+ stars) Python and TypeScript SDK from AWS
• Steering handlers/hooks that catch agent mistakes before execution
• Native Bedrock and AWS AgentCore integration, plus any-LLM support

✦ WhyA Google Agent Development Kit (ADK) alternative — Open-source (MIT) framework from Stanford NLP, 37k+ GitHub stars.

• Open-source (MIT) framework from Stanford NLP, 37k+ GitHub stars
• Compiles/optimizes prompts automatically against metrics instead of manual prompt tuning
• Production use at Databricks, Shopify, Dropbox, AWS; Shopify reports ~550x cost reduction