Pydantic AI vs Google ADK
Google’s Agent Development Kit is an agent platform built around Gemini and Vertex AI: workflow graphs, evaluation, a dev UI, and deploy commands for Cloud Run, GKE, Docker and Agent Engine. Pydantic AI is a provider-agnostic library you run on your own infrastructure, with pydantic-graph for workflows, Pydantic Evals, a web chat UI, and Pydantic Logfire to watch it all run.
Pydantic AI is one part of a stack: the Harness SDK for capabilities and complete agents, Pydantic Evals for evaluation, Pydantic Graph for graph-based workflows, Pydantic Logfire for observability, and Pydantic itself for validation. The tables below cover the whole of it.
Already built on Google ADK? The migrating-google-adk-to-pydantic-ai skill ports an existing application to Pydantic AI one working path at a time, preserving behavior rather than translating API names.
| Google ADK | Pydantic AI and Harness SDK | |
|---|---|---|
| Language | Python | Python |
| License | Apache-2.0 | MIT |
| Model providers | Gemini first (LiteLlm, AnthropicLlm exist) | Many |
| Extensibility | Tools, plugins | Capabilities and toolsets; 80+ with the Harness SDK |
| Harnesses | Build your own; shell, file tools, sandboxes and compaction ship | Built-in Coder and Researcher, or compose your own |
| Observability | OpenTelemetry | OpenTelemetry, including Pydantic Logfire |
| Enterprise support | None documented for ADK; Google Cloud support for the cloud | For the framework itself, no platform required |
| Durable execution | Yes | Nine integrations |
| Interfaces | CLI, web, A2A | CLI, web chat, AG-UI, Vercel AI, ACP (experimental), GitHub Agentic Workflows |
| Realtime voice | Yes | Realtime |
| Evals | Yes | Pydantic Evals |
| Image generation | No | Image Generation |
| Google ADK | Pydantic AI and Harness SDK | |
|---|---|---|
| Multi-agent | Yes | Subagents, delegation, or pydantic-graph |
| Planning | Prompt-level only | Planning |
| Skills | Yes (experimental) | Skills |
| Memory | Yes | Memory |
| Compaction | Yes | Compaction |
| Guardrails | Yes | Guardrails |
| Code sandboxes | Yes | Execution environments |
| Browser use | Yes | Web & research |
Can I use Pydantic AI on Google Cloud? Yes. Run agents on Gemini and Model Garden models on Google Cloud, including Claude on Google Cloud, with Google Cloud embeddings, Gemini image generation and voice agents on Gemini Live. The Harness adds Google Workspace tools, and the realtime deployment guide covers Cloud Run. Can we run on our cloud? covers AWS and Azure too.
Can I build a coding agent on Pydantic AI? Yes. Give your agent the
Coder() capability, or assemble your own from the
same Agent; the harness repository has a
complete coding agent
built from the pieces Coder puts together.
Can I run my agents in CI? Yes. GitHub Agentic Workflows runs Pydantic AI agents
from a Markdown workflow file in GitHub Actions, or run a Python script directly with uv run;
nothing requires an Action.
Last checked: 2026-09-26