If you are on Google Cloud and building multi-agent systems, ADK plus Agent Engine is a coherent, well-supported stack, and the built-in debugging UI is genuinely useful. If you are not committed to GCP, the Google-flavored defaults and setup friction are harder to justify against more neutral frameworks like LangGraph or Pydantic AI.
What is Google Agent Development Kit (ADK)?
The Agent Development Kit is Google's open-source framework for building agents and multi-agent systems in Python and Java, the same framework that powers agents inside Google's own products. It treats multi-agent composition as a first-class concept, with specialized agents delegating to each other, ships a built-in web UI for local debugging, and supports the A2A protocol and MCP for interoperability. It is model-agnostic in principle but pairs most naturally with Gemini and deploys most smoothly to Vertex AI Agent Engine, Google's managed agent runtime, now part of the Gemini Enterprise agent platform.
Best for
Teams building multi-agent systems, especially those already on Google Cloud and Gemini.
Not for
Teams avoiding Google Cloud lock-in, simple single-agent apps, or non-developers.
Strengths
- Multi-agent hierarchies and delegation are first-class, not bolted on
- Built-in developer UI for stepping through and debugging agent runs locally
- Streaming support, including bidirectional audio and video for live agents
- Supports MCP and the A2A protocol for cross-vendor agent interoperability
- Available in Python and Java, a rarity among agent frameworks
- Managed deployment path via Vertex AI Agent Engine when you do not want to run infrastructure
Limitations
- Clearly optimized for Gemini and Google Cloud, so other models and clouds feel second-class
- Google Cloud setup, IAM, and service accounts add real friction for teams new to GCP
- Younger than the established frameworks, with a smaller community and fewer third-party resources
- The managed Agent Engine runtime bills per vCPU-hour and GB-hour, which needs watching for long-running agents
- Google's history of renaming and reshuffling cloud products makes some teams wary of platform churn
Google Agent Development Kit (ADK) pricing
Free open-source framework; Google monetizes through Gemini API usage and the metered Vertex AI Agent Engine runtime.
Pricing reflects public plans as of July 2, 2026 and can change. Check Google Agent Development Kit (ADK) for the latest.
Google Agent Development Kit (ADK) FAQ
Is Google ADK free?
Yes, the framework is Apache 2.0 open source with no license fee. You pay for model calls, typically Gemini, and for hosting, whether your own infrastructure or the metered Vertex AI Agent Engine runtime, which has a small free monthly tier.
Does Google ADK only work with Gemini?
No, it is model-agnostic and can use other providers through LiteLLM and similar integrations, but the developer experience, tooling, and documentation are clearly optimized for Gemini and Vertex AI. Expect more friction with non-Google models.
Google ADK vs LangGraph?
ADK is stronger on out-of-the-box multi-agent composition, the local debugging UI, and the managed deployment story on Google Cloud. LangGraph is more cloud-neutral, has a larger community, and gives finer control over stateful graphs. Teams on GCP lean ADK; teams that want portability lean LangGraph.
Do I need Google Cloud to use ADK?
No, you can run ADK agents anywhere Python or Java runs, including locally or in your own containers. In practice, though, the smoothest experience, especially managed deployment via Agent Engine and Gemini access, assumes a Google Cloud project.
Looking at alternatives? ADK is a different tool for a different job, a serious framework for engineering teams building multi-agent products on Google Cloud. Autonoly handles the surrounding business workflows, the everyday automations that should not require a GCP project, IAM roles, or a deployment pipeline to exist. See the Autonoly review.