05 · Framework (Agent Development Kit 2.0) · LAST REVIEWED SEPTEMBER 2026
Google ADK review: the widest language coverage, first-class A2A
SHORT ANSWER
Google ADK
Rank 05 of 10
| Criterion | Weight | Score | Why |
|---|---|---|---|
| Cross-framework interop | 20 | 8.0 | Google created A2A and donated it to the Linux Foundation; ADK ships A2A quickstarts for Python, Go, Java and Kotlin. MCP is supported for tools. |
| Multi-agent coordination model | 18 | 8.0 | Sequential, Parallel and Loop workflow agents, custom workflows, graph-based workflows (new in 2.0) and delegation through a Task API. |
| Shared context and memory | 14 | 6.5 | State lives inside the ADK application. Across apps, A2A keeps agents opaque by design, so shared context is something you build. |
| Production reliability | 12 | 7.5 | Enterprise-scale positioning, but ADK 2.0 has breaking changes from 1.x, so plan migration work. |
| Human-in-the-loop | 10 | 6.5 | No dedicated human-participation surface in the docs we reviewed; approval steps are built into your workflows. |
| Observability | 10 | 7.0 | Debugging is part of the kit; deeper monitoring comes from Google Cloud. |
| Languages and deployment | 8 | 9.0 | Python, TypeScript/JS, Go, Java and Kotlin. Agent Runtime on Vertex AI, Cloud Run, GKE or any container. |
| Pricing clarity | 8 | 6.0 | The framework is free (Apache 2.0). Managed runtime and model usage are billed by Google Cloud; we have not summarized those rates. |
What is Google ADK at a glance?
| Type | Framework (Agent Development Kit 2.0) |
|---|---|
| Coordination model | Sequential, parallel, loop, graph (2.0); Task API |
| A2A | Yes (native) |
| MCP | Yes |
| Languages | Python, TS/JS, Go, Java, Kotlin |
| License | Apache 2.0 |
| Hosting | Agent Runtime (Vertex AI), Cloud Run, GKE, any container |
| Pricing | Free framework; Google Cloud usage |
| Works with BAND | Listed on band.ai/integrations |
Source: adk.dev · github.com/google/adk-python · a2a-protocol.org · Reviewed Sep 2026
What is Google ADK?
The Agent Development Kit is Google's Apache 2.0 "open-source agent development framework that lets you build, debug, and deploy reliable AI agents at enterprise scale." The current version is ADK 2.0, which has breaking changes from 1.x. It is built for Gemini and Vertex AI, but it is model-agnostic.
How does ADK coordinate agents?
Workflow agents: Sequential, Parallel and Loop. Custom workflows. Graph-based workflows, new in 2.0. Multi-agent delegation runs through a Task API. That covers most of the patterns a single application needs.
Why does ADK score well on interop but lower on shared context?
Because of how A2A is designed. Google created A2A and donated it to the Linux Foundation, and ADK has A2A quickstarts for Python, Go, Java and Kotlin, so ADK agents are easy to call from other frameworks and vice versa. A2A deliberately keeps agents opaque: they interact "without needing to share internal memory, tools, or proprietary logic." That is the right protocol design, but it means shared context across agents is something you build. Inside an ADK app, state is well handled; across apps, it is up to you or a collaboration layer such as BAND.
How much does it cost?
The framework is free (Apache 2.0). Agent Runtime on Vertex AI, Cloud Run, GKE and model usage are billed by Google Cloud.
Source: adk.dev · Reviewed Sep 2026
What are the strengths and limitations of Google ADK?
Strengths
- Widest language coverage
- First-class A2A
- Tight Gemini and Vertex integration while model-agnostic
Limitations
- Best experience on Google Cloud
- 2.0 breaking changes
Should you choose Google ADK or look elsewhere?
Choose Google ADK if
- your team works in Java, Kotlin or Go as well as Python or TypeScript
- you want A2A from day one
- you deploy on Google Cloud
Look elsewhere if
- you are mid-project on ADK 1.x and cannot absorb breaking changes yet
- you need people to take part while agents work (BAND)
- you want built-in tracing on a par with LangSmith
What should you read after the Google ADK review?
What do readers ask about Google ADK?
Which languages does Google ADK support?
Python, TypeScript/JavaScript, Go, Java and Kotlin.
Does ADK only work with Gemini?
No. It is optimized for Gemini and Vertex AI but is model-agnostic.
What changed in ADK 2.0?
Graph-based workflows were added, and there are breaking changes from 1.x, so check the migration notes before upgrading.
Can ADK agents collaborate with LangGraph or CrewAI agents?
Over A2A, yes. For shared rooms with common history and humans, BAND lists Google ADK, LangGraph and CrewAI among its integrations.
Running agents on more than one framework? BAND connects them in shared rooms.
See how BAND works