---
title: Transport
description: How to communicate with the FastAPI app
icon: car
---
FastAPI-MCP uses ASGI transport by default, which means it communicates directly with your FastAPI app without making HTTP requests. This is more efficient and doesn't require a base URL.
It's not even necessary that the FastAPI server will run.
If you need to specify a custom base URL or use a different transport method, you can provide your own `httpx.AsyncClient`:
```python {7-10, 14}
import httpx
from fastapi import FastAPI
from fastapi_mcp import FastApiMCP
app = FastAPI()
custom_client = httpx.AsyncClient(
base_url="https://api.example.com",
timeout=30.0
)
mcp = FastApiMCP(
app,
http_client=custom_client
)
mcp.mount()
```