tiangolo/fastapi · error · HTTPException

No Jessica token provided

Error message

No Jessica token provided

What it means

Raised by the get_query_token dependency when the query parameter named token is not equal to "jessica", returning HTTP 400. Unlike the header checks, this validates a URL query parameter, demonstrating FastAPI's ability to gate the app/router on a query value.

Source

Thrown at docs_src/bigger_applications/app_an_py310/dependencies.py:13

from typing import Annotated

from fastapi import Header, HTTPException


async def get_token_header(x_token: Annotated[str, Header()]):
    if x_token != "fake-super-secret-token":
        raise HTTPException(status_code=400, detail="X-Token header invalid")


async def get_query_token(token: str):
    if token != "jessica":
        raise HTTPException(status_code=400, detail="No Jessica token provided")

View on GitHub (pinned to 42a41db11f)

Solutions

1. Append ?token=jessica to the request URL.
2. When using TestClient, pass params={"token": "jessica"}.
3. Confirm the param name and value against the dependency definition.

Example fix

# before
client.get("/")
# after
client.get("/", params={"token": "jessica"})

# Ensure the token query param is set
params = {"token": "jessica"}
client.get("/", params=params)

def has_query_token(params: dict) -> bool:
    return params.get("token") == "jessica"

When it happens

Trigger: A request whose URL lacks ?token=jessica, e.g. GET / without the query param, or GET /?token=wrong.

Common situations: Clients building URLs without the token query param; query stripped by a proxy/redirect; assuming auth is header-only.

Related errors

• X-Token header invalid
• X-Token header invalid
• X-Key header invalid
• X-Token header invalid
• X-Key header invalid

AI-assisted analysis of tiangolo/fastapi@42a41db11f (2026-08-04). Data as JSON: /data/errors/1365ee70a9f6ea2e.json. Report an issue: GitHub.