Query Parameters in Python
From the FastAPI cheat sheet · Path & Query Parameters · verified Jul 2026
Query Parameters
Accept query string parameters with defaults and validation.
python
from fastapi import FastAPI, Query
app = FastAPI()
# Basic query parameters
@app.get("/items/")
async def read_items(skip: int = 0, limit: int = 10):
return {"skip": skip, "limit": limit}
# GET /items/?skip=5&limit=20
# Required + validated
@app.get("/search/")
async def search(
q: str = Query(min_length=3, max_length=50),
):
return {"query": q}💡 Any function parameter not in the URL path is automatically a query parameter
⚡ Use Query() for string validation: min_length, max_length, pattern (regex)
📌 Use list[str] with Query() to accept repeated query params (?tag=a&tag=b)
🟢 Set deprecated=True to mark a parameter as deprecated in the docs
queryparametersvalidation