Top 9 of 15 alternatives
Google Agent Development Kit (ADK) alternatives like Letta
The closest alternatives to Google Agent Development Kit (ADK) in August 2026 are Letta, AutoGen and OpenAI Agents SDK (Python).
9 agents compared · 9 with a free plan · prices checked 18 September–1 November 2026
Reviewed by The Agents Index editorial team.
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Google Agent Development Kit (ADK) and its alternatives at a glance
| Agent | Best for | Starts at | Better than Google Agent Development Kit (ADK) at | Checked |
|---|---|---|---|---|
| Google Agent Development Kit (ADK) | Teams that want Google's own official, actively-developed agent SDK, especially polyglot teams (Python/Go/Java/TypeScript/Kotlin) or anyone building multi-agent systems that need to interoperate across vendors via the A2A protocol. | On quote source | 15 September 2026 | |
| Letta | Developers and researchers who specifically need an agent whose memory, skills and identity genuinely persist and evolve across long-running sessions, rather than reset on every call. | Free, then $20 a month source | Writes code, Debugs and fixes | 2 September 2026 |
| AutoGen | Python or .NET developers and researchers exploring multi-agent orchestration who want a mature, free, self-hosted framework. | Free source | Writes code, In a browser | 19 September 2026 |
| OpenAI Agents SDK (Python) | Developers who want the fastest, lightest way to ship a straightforward agent (support triage, a tool-using assistant or a sandboxed coding agent) with tracing and guardrails included. | Free source | 18 October 2026 | |
| LangGraph | Engineering teams building production agents who need cyclical graphs, durable state and replayable runs | Free, then $39 a seat a month source | In your pipeline, In a browser | 2 September 2026 |
| Microsoft Agent Framework | .NET or Python teams already invested in Azure or Microsoft Foundry who want one supported agent SDK, an optional managed hosting path, and a documented migration off AutoGen or Semantic Kernel. | Free source | 19 September 2026 | |
| CrewAI | Developers who want to stand up a role-based, collaborating multi-agent system quickly in Python, with a stable MIT-licensed core and a hosted build and runtime for production. | Free source | Done-for-you service, In a browser | 13 September 2026 |
| LiveKit Agents | Engineering teams that want to own their voice-agent stack end to end, self-hosted or on LiveKit Cloud, without being locked into one vendor's API. | Free, then $50 a month source | In a browser, How it meters | 2 September 2026 |
| Agno | Python developers who want an Apache 2.0 SDK with memory, knowledge, learning, guardrails and a Control Plane they run inside their own cloud account, and who are comfortable running Docker or a cloud deploy template themselves. | Free, then $150 a month source | Reviews code, Done-for-you service | 17 October 2026 |
| LangChain | Engineering teams building a bespoke, production-grade agent who want the largest integration ecosystem plus real stateful control. | Free, then $39 a seat a month source | Writes code, Done-for-you service | 18 September 2026 |
Closest alternatives to Google Agent Development Kit (ADK)
The ones people open most here come first, then the closest matches. How we check
Where Google Agent Development Kit (ADK) falls short: It is a code library plus an optional managed layer, not a no-code product by default. The low-code Agent Designer sits in a separate part of the wider Gemini Enterprise Agent Platform, not inside ADK itself.
- From Free
Stateful agent harness, cloud and SDK for agents with persistent, git-versioned memory.
Why it's on this listWrites code: YesAgents edit and create files in your repository, including from GitHub issues and PRs.
Watch forSmaller ecosystem and community than LangChain, LlamaIndex or Microsoft AutoGen.
- From Free
Open-source Microsoft framework for building single and multi-agent AI applications in Python.
Why it's on this listWrites code: YesShips a dedicated coder agent whose system prompt specialises it for writing code and creating artifacts, used inside Magentic-One teams alongside a terminal agent.
Better than Google Agent Development Kit (ADK) at- In a browser: Yes ↗
Watch forIt is a code library, not a hosted service. You build, host and operate the agents yourself.
- From Free
Open-source Python framework for building agents with tools, handoffs, guardrails and tracing.
Watch forNo automatic step-by-step checkpointing, `RunState` only snapshots at human-in-the-loop approval pauses, so you manage durable state yourself outside of that.
The rest of the shortlist
- From Free
LangGraph
Open-source orchestration framework and runtime for stateful, long-running LLM agents, from LangChain.
Watch for: No native token-budget or cost-limit management in the framework. Cost caps have to be handled at the model-integration level.
- From FreeCompare
Microsoft Agent Framework
Open-source .NET, Python and Go SDK for building AI agents and graph-based multi-agent workflows.
Watch for: It is a code library plus an optional managed layer, not a no-code product. You (or Foundry Hosted Agents) run and operate it.
- From Free
CrewAI
Open-source multi-agent framework with a managed platform for deploying and governing agent workflows.
Watch for: Pricing jumps directly from a free 50-execution Basic tier to custom Enterprise, with no self-serve plan in between
- From Free
LiveKit Agents
Open-source Python and Node.js framework for voice AI agents, with LiveKit Cloud hosting, telephony and observability.
Watch for: A framework, not a no-code or dashboard-first builder. Expect to write and deploy real code, unlike this category's more configured rivals.
- From Free
Agno
Python SDK, self-hosted AgentOS runtime and hosted control plane for running agents as a service.
Watch for: The 3.2-microsecond / 5.2 KiB figure is measured on Agno's own published harness. Independent, reproducible benchmarks against LangGraph on neutral hardware were not found.
- From Free
LangChain
Open source agent frameworks plus LangSmith, a hosted platform to trace, evaluate, deploy and govern agents.
Watch for: Fast-moving: core abstractions have changed across major versions, so older tutorials can mislead.
Compare Google Agent Development Kit (ADK) with the shortlist
Compare alternatives to Google Agent Development Kit (ADK)
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Questions buyers ask
What are the best alternatives to Google Agent Development Kit (ADK)?
Letta, AutoGen and OpenAI Agents SDK (Python) are the closest. They share the most of Google Agent Development Kit (ADK)'s features.
What is the cheapest alternative to Google Agent Development Kit (ADK)?
All 9 have a free plan: Letta, AutoGen, OpenAI Agents SDK (Python), LangGraph and Microsoft Agent Framework and 4 more.
When were these prices checked?
Between 18 September 2026 and 1 November 2026, each read on the maker's own pricing page.
Sources and method
Closest first: most of Google Agent Development Kit (ADK)'s features, then the fewest gaps. How we check
Every price here was read on the maker's own pricing page.
- Google Agent Development Kit (ADK): adk.dev/pricing, checked 30 October 2026
- Letta: docs.letta.com/pricing, checked 1 November 2026
- AutoGen: github.com/microsoft/autogen/blob/main/LICENSE-CODE, checked 19 September 2026
- OpenAI Agents SDK (Python): raw.githubusercontent.com/openai/openai-agents-python/main/LICENSE, checked 20 September 2026
- LangGraph: langchain.com/pricing, checked 1 November 2026
- Microsoft Agent Framework: github.com/microsoft/agent-framework/blob/main/LICENSE, checked 19 September 2026
- CrewAI: crewai.com/pricing, checked 30 October 2026
- LiveKit Agents: livekit.com/pricing, checked 24 October 2026
- Agno: agno.com/pricing, checked 29 October 2026
- LangChain: langchain.com/pricing, checked 18 September 2026
What AI answers name as Google Agent Development Kit (ADK) alternatives
We asked for Google Agent Development Kit (ADK) alternatives and counted the agents we list in each answer.
theagentsindex.com · 1 answer from Perplexity, collected 13 October 2026.
What changed in the index
Agents we’ve just listed and every plan whose price changed.