How to return plain text in FastAPI

December 20, 2023

In this example, the entrypoint http://127.0.0.1:8000/ returns formatted text:

"Hello \"World\"!"

The quotes are masked by a slash, and quotes are added both at the beginning and at the end. How to return unformatted text, identical to my string Hello "World"!.

import uvicorn
from fastapi import FastAPI

app = FastAPI()


@app.get("/",)
def read_root():
    return 'Hello "World"!'


uvicorn.run(app)

>Solution :

When you return a string from a FastAPI endpoint, FastAPI will automatically convert it to a JSON response, which is why the quotes are being escaped in your example. JSON strings must escape double quotes with a backslash.

If you want to return unformatted text (plain text) and not JSON, you can do so by using FastAPI’s PlainTextResponse object (docs here).

I’m using FastApi version 0.104 here:

import uvicorn
from fastapi import FastAPI
from fastapi.responses import PlainTextResponse

app = FastAPI()


@app.get(
    "/",
    response_class=PlainTextResponse,
)
def read_root():
    return 'Hello "World"!'


uvicorn.run(app)