Bring Your Own FastAPI App

Integrate your own FastAPI app with AgentOS.

AgentOS is built on FastAPI, which means you can easily integrate your existing FastAPI applications or add custom routes and routers to extend your agent’s capabilities.

Quick Start

The simplest way to bring your own FastAPI app is to pass it to the AgentOS constructor:

from fastapi import FastAPI
from agno.agent import Agent
from agno.models.openai import OpenAIResponses
from agno.os import AgentOS

# Create your custom FastAPI app
app = FastAPI(title="My Custom App")

# Add your custom routes
@app.get("/status")
async def status_check():
    return {"status": "healthy"}

# Pass your app to AgentOS
agent_os = AgentOS(
    agents=[Agent(id="basic-agent", model=OpenAIResponses(id="gpt-5.2"))],
    base_app=app  # Your custom FastAPI app
)

# Get the combined app with both AgentOS and your routes
app = agent_os.get_app()

Your custom FastAPI app can have its own middleware and dependencies.

If you have your own CORS middleware, it will be updated to include the AgentOS allowed origins, to make the AgentOS instance compatible with the Control Plane. Otherwise, the appropriate CORS middleware will be added to the app.

Adding Middleware

You can add any FastAPI middleware to your custom FastAPI app and it will be respected by AgentOS.

Agno also provides some built-in middleware for common use cases, including authentication.

See the Middleware page for more details.

Running with FastAPI CLI

AgentOS applications are compatible with the FastAPI CLI for development.

First, install the FastAPI CLI:

Install FastAPI CLI

uv pip install "fastapi[standard]"

Then run the app:

Run with FastAPI CLI

fastapi run your_app.py

fastapi run your_app.py --reload

fastapi run your_app.py --host 0.0.0.0 --port 8000

Running in Production

For production deployments, you can use any ASGI server:

Uvicorn

uvicorn main:app --host 0.0.0.0 --port 8000 --workers 4

gunicorn main:app -w 4 -k uvicorn.workers.UvicornWorker --bind 0.0.0.0:8000

fastapi run main.py --host 0.0.0.0 --port 8000

Adding More Routes

Register as many routes on your app as you need:

custom_fastapi_app.py

from agno.agent import Agent
from agno.db.sqlite import SqliteDb
from agno.models.anthropic import Claude
from agno.os import AgentOS
from agno.tools.hackernews import HackerNewsTools
from fastapi import FastAPI

# Set up the database
db = SqliteDb(db_file="tmp/agentos.db")

# Set up the agent
web_research_agent = Agent(
    name="Basic Agent",
    model=Claude(id="claude-sonnet-4-5"),
    db=db,
    tools=[HackerNewsTools()],
    add_history_to_context=True,
    num_history_runs=3,
    add_datetime_to_context=True,
    markdown=True,
)

# Create custom FastAPI app
app: FastAPI = FastAPI(
    title="Custom FastAPI App",
    version="1.0.0",
)

# Add your own routes
@app.get("/customers")
async def get_customers():
    return [
        {
            "id": 1,
            "name": "John Doe",
            "email": "[e-mail]",
        },
        {
            "id": 2,
            "name": "Jane Doe",
            "email": "[e-mail]",
        },
    ]


# Set up the AgentOS app by passing your FastAPI app
agent_os = AgentOS(
    description="Example app with custom routers",
    agents=[web_research_agent],
    base_app=app,
)

app = agent_os.get_app()


if __name__ == "__main__":
    """Run the AgentOS application.

    You can see the docs at:
    http://localhost:7777/docs

    """
    agent_os.serve(app="custom_fastapi_app:app", reload=True)

Run it end to end:

1. Set up your virtual environment

   Mac

   uv venv --python 3.12
   source .venv/bin/activate
   

   uv venv --python 3.12
   .venv\Scripts\activate
   
2. Set environment variables

   export ANTHROPIC_API_KEY=your_anthropic_api_key
   
3. Install dependencies

   uv pip install -U agno anthropic openai fastapi uvicorn sqlalchemy
   
4. Run the example

   python custom_fastapi_app.py
   

Middleware and Dependencies

You can add middleware and dependencies to your custom FastAPI app:

from fastapi import FastAPI, Depends, HTTPException
from fastapi.middleware.cors import CORSMiddleware
from fastapi.security import HTTPBearer

app = FastAPI()

# Add CORS middleware
app.add_middleware(
    CORSMiddleware,
    allow_origins=["https://yourdomain.com"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

# Security dependency
security = HTTPBearer()

async def verify_token(token: str = Depends(security)):
    if token.credentials != "your-secret-token":
        raise HTTPException(status_code=401, detail="Invalid token")
    return token

# Protected route
@app.get("/protected", dependencies=[Depends(verify_token)])
async def protected_endpoint():
    return {"message": "Access granted"}

# Integrate with AgentOS
agent_os = AgentOS(
    agents=[Agent(id="basic-agent", model=OpenAIResponses(id="gpt-5.2"))],
    base_app=app
)

app = agent_os.get_app()

Access AgentOS Routes

You can programmatically access and inspect the routes added by AgentOS:

agent_os = AgentOS(agents=[agent])
app = agent_os.get_app()

# Get all routes
routes = agent_os.get_routes()

for route in routes:
    print(f"Route: {route.path}")
    if hasattr(route, 'methods'):
        print(f"Methods: {route.methods}")

Developer Resources

• AgentOS Reference
• FastAPI Documentation