# The CopilotKit Stack

From frontend platform to model provider — every layer, every choice

Frontend Platform
Where your UI runs
Web
React
Angular
Svelte
Vue
TanStack
Native
React Native
SwiftUI
Android
Messaging
Slack
Teams
WhatsApp
Chat UI
Pre-built → customized → headless
OPINIONATED
FULL CONTROL
CopilotChat
CopilotSidebar
CopilotPopup
CSS Variables
Slots
Custom Sub-Components
Headless (useAgent)
Generative UI
Controlled → declarative → open
MORE CONTROL
MORE FREEDOM
Controlled
Tool-Based
Agentic
Interrupt-Based
Declarative (BYOC)
A2UI
Hashbrown
JSON Render
OpenGenUI
Tambo
Open
Fully Agent-Generated
MCP Apps
Interaction Patterns
How users and agents collaborate
Human in the Loop
Frontend Tools
Tool Rendering
Readables
Agent Context
Suggestions
Voice
Multi-modal
State Sync
Shared state between UI and agent
State Reading
State Writing
State Streaming
I/O Schemas
State Rendering

### CopilotKit

Runtime · SDK · React Bindings

### AG-UI Protocol

Agent ↔ UI interop standard

Agent Frameworks
Libraries you write agent code with
Agent ↔ Agent
A2A
Open Agent Spec
Agents communicate
with each other
LangGraph
Mastra
CrewAI
PydanticAI
AG2
Agno
LlamaIndex
Langroid
AWS Strands
Spring AI
MAF
Agent ↔ Tools
MCP
Agents discover &
call external tools
Agent Platforms
Where you deploy and run your agents
LangSmith / LangGraph Cloud
AWS Agent Core
Google Vertex AI
Azure AI Foundry
Cloudflare Workers
Vercel
Render / Railway / Fly
LLM Providers
The models powering your agents
OpenAI
Anthropic
Google
AWS Bedrock
Azure OpenAI
Groq
Ollama
Any OpenAI-compatible