And we as developers keep improving the code as we find those bugs and as we implement new features (possibly adding new bugs too 😅).

### Small Errors Automatically Handled

When building web APIs with FastAPI, if there's an error in our code, FastAPI will normally contain it to the single request that triggered the error. 🛡

///

**FastAPI**는 모두 Pydantic을 기반으로 되어 있습니다.

이 모든 것이 실제로 어떻게 사용되는지에 대해서는 [자습서 - 사용자 안내서](tutorial/index.md){.internal-link target=_blank} 에서 더 많이 확인하실 수 있습니다.

## **FastAPI**에서의 타입 힌트

**FastAPI**는 여러 부분에서 타입 힌트의 장점을 취하고 있습니다.

**FastAPI**에서 타입 힌트와 함께 매개변수를 선언하면 장점은:

* **에디터 도움**.
* **타입 확인**.

...그리고 **FastAPI**는 같은 정의를 아래에도 적용합니다:

# Encoders - `jsonable_encoder`

from typing import Optional

from dirty_equals import IsDict
from fastapi import APIRouter, FastAPI
from fastapi.testclient import TestClient

app = FastAPI()


user_router = APIRouter()
item_router = APIRouter()


@user_router.get("/")
def get_users():
    return [{"user_id": "u1"}, {"user_id": "u2"}]


@user_router.get("/{user_id}")
def get_user(user_id: str):
    return {"user_id": user_id}

from typing import Union

from dirty_equals import IsDict
from fastapi import Body, Cookie, FastAPI, Header, Path, Query
from fastapi.testclient import TestClient
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    data: str


@app.post("/examples/")
def examples(
    item: Item = Body(
        examples=[
            {"data": "Data in Body examples, example1"},
        ],

from fastapi.testclient import TestClient

from docs_src.path_operation_advanced_configuration.tutorial001 import app

client = TestClient(app)


def test_get():
    response = client.get("/items/")
    assert response.status_code == 200, response.text
    assert response.json() == [{"item_id": "Foo"}]


def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text

from dirty_equals import IsDict
from fastapi.testclient import TestClient

from docs_src.dataclasses.tutorial001 import app

client = TestClient(app)


def test_post_item():
    response = client.post("/items/", json={"name": "Foo", "price": 3})
    assert response.status_code == 200
    assert response.json() == {
        "name": "Foo",
        "price": 3,
        "description": None,
        "tax": None,
    }

import pytest
from dirty_equals import IsDict
from fastapi.testclient import TestClient

from docs_src.dependencies.tutorial004 import app

client = TestClient(app)


@pytest.mark.parametrize(
    "path,expected_status,expected_response",
    [
        (
            "/items",
            200,
            {
                "items": [
                    {"item_name": "Foo"},
                    {"item_name": "Bar"},

import pytest
from dirty_equals import IsDict
from fastapi.testclient import TestClient

from docs_src.dependencies.tutorial004_an import app

client = TestClient(app)


@pytest.mark.parametrize(
    "path,expected_status,expected_response",
    [
        (
            "/items",
            200,
            {
                "items": [
                    {"item_name": "Foo"},
                    {"item_name": "Bar"},

from fastapi.testclient import TestClient

from docs_src.behind_a_proxy.tutorial002 import app

client = TestClient(app)


def test_main():
    response = client.get("/app")
    assert response.status_code == 200
    assert response.json() == {"message": "Hello World", "root_path": "/api/v1"}


def test_openapi():
    response = client.get("/openapi.json")
    assert response.status_code == 200
    assert response.json() == {