def test_openapi_schema(client: TestClient):
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text
    assert response.json() == {
        "openapi": "3.1.0",
        "info": {"title": "FastAPI", "version": "0.1.0"},
        "paths": {},

It uses Marshmallow underneath to do the data validation. And it was created by the same developers.

It's a great tool and I have used it a lot too, before having **FastAPI**.

/// info

Webargs was created by the same Marshmallow developers.

///

/// check | Inspired **FastAPI** to

Have automatic validation of incoming request data.

///

def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text
    assert response.json() == {
        "openapi": "3.1.0",
        "info": {"title": "FastAPI", "version": "0.1.0"},
        "paths": {
            "/product": {
                "get": {
                    "summary": "Create Item",
                    "operationId": "create_item_product_get",

                },
                "required": ["loc", "msg", "type"],
                "title": "ValidationError",
                "type": "object",
            },
        }
    },
    "info": {"title": "FastAPI", "version": "0.1.0"},
    "openapi": "3.1.0",
    "paths": {
        "/": {
            "get": {
                "operationId": "get_deps__get",
                "parameters": [

                    },
                    "required": ["loc", "msg", "type"],
                    "title": "ValidationError",
                    "type": "object",
                },
            }
        },
        "info": {"title": "FastAPI", "version": "0.1.0"},
        "openapi": "3.1.0",
        "paths": {
            "/{repeated_alias}": {
                "get": {

def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text
    assert response.json() == {
        "openapi": "3.1.0",
        "info": {"title": "FastAPI", "version": "0.1.0"},
        "paths": {
            "/": {
                "post": {
                    "summary": "Post",
                    "operationId": "post__post",

client = TestClient(app)


def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text
    assert response.json() == {
        "openapi": "3.1.0",
        "info": {"title": "FastAPI", "version": "0.1.0"},
        "paths": {
            "/a": {
                "get": {
                    "responses": {
                        "500": {

        ]
    }


def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text
    assert response.json() == {
        "openapi": "3.1.0",
        "info": {"title": "FastAPI", "version": "0.1.0"},
        "paths": {
            "/items/{item_id}": {
                "get": {
                    "operationId": "read_item_items__item_id__get",
                    "parameters": [

// Macro to verify that the field `struct_size` of STRUCT_OBJ is initialized.
// `struct_size` is used for struct member compatibility check between core TF
// and plug-ins with the same C API minor version. More info here:
// https://github.com/tensorflow/community/blob/master/rfcs/20200612-stream-executor-c-api/C_API_versioning_strategy.md
#define TF_VALIDATE_STRUCT_SIZE(STRUCT_NAME, STRUCT_OBJ, SIZE_VALUE_NAME) \

def test_openapi_schema(client: TestClient):
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text
    assert response.json() == {
        "openapi": "3.1.0",
        "info": {"title": "FastAPI", "version": "0.1.0"},
        "paths": {
            "/users/me": {
                "get": {
                    "responses": {
                        "200": {