But then, when you open the integrated docs UI (the frontend), it would expect to get the OpenAPI schema at `/openapi.json`, instead of `/api/v1/openapi.json`.

So, the frontend (that runs in the browser) would try to reach `/openapi.json` and wouldn't be able to get the OpenAPI schema.

Because we have a proxy with a path prefix of `/api/v1` for our app, the frontend needs to fetch the OpenAPI schema at `/api/v1/openapi.json`.

```mermaid

In this case you will have to ensure that each operation ID is **unique** in some other way.

For example, you could make sure that each *path operation* has a tag, and then generate the operation ID based on the **tag** and the *path operation* **name** (the function name).

### Custom Generate Unique ID Function

            ),
        ],
        scope: Annotated[
            str,
            Form(),
            Doc(
                """
                A single string with actually several scopes separated by spaces. Each
                scope is also a string.

                For example, a single string with:

                ```python
                "items:read items:write users:read profile openid"
                ````

* `TRACE`

In the HTTP protocol, you can communicate to each path using one (or more) of these "methods".

---

When building APIs, you normally use these specific HTTP methods to perform a specific action.

Normally you use:

* `POST`: to create data.
* `GET`: to read data.
* `PUT`: to update data.
* `DELETE`: to delete data.

So, in OpenAPI, each of the HTTP methods is called an "operation".

**Requests** is a library to *interact* with APIs (as a client), while **FastAPI** is a library to *build* APIs (as a server).

They are, more or less, at opposite ends, complementing each other.

Requests has a very simple and intuitive design, it's very easy to use, with sensible defaults. But at the same time, it's very powerful and customizable.

That's why, as said in the official website:

* Security - HTTPS
* Running on startup
* Restarts
* Replication (the number of processes running)
* Memory
* Previous steps before starting

* The process can be **terminated** (or "killed") by you, or by the operating system. At that point, it stops running/being executed, and it can **no longer do things**.
* Each application that you have running on your computer has some process behind it, each running program, each window, etc. And there are normally many processes running **at the same time** while a computer is on.

* `dependencies`: they all need that `X-Token` dependency we created.

So, instead of adding all that to each *path operation*, we can add it to the `APIRouter`.

```Python hl_lines="5-10  16  21" title="app/routers/items.py"
{!../../../docs_src/bigger_applications/app/routers/items.py!}
```

As the path of each *path operation* has to start with `/`, like in:

```Python hl_lines="1"
@router.get("/{item_id}")

    ```

This means:

* The variable `prices` is a `dict`:
    * The keys of this `dict` are of type `str` (let's say, the name of each item).
    * The values of this `dict` are of type `float` (let's say, the price of each item).

#### Union

You can declare that a variable can be any of **several types**, for example, an `int` or a `str`.

```

## Metadata for tags

You can also add additional metadata for the different tags used to group your path operations with the parameter `openapi_tags`.

It takes a list containing one dictionary for each tag.

Each dictionary can contain:

* `name` (**required**): a `str` with the same tag name you use in the `tags` parameter in your *path operations* and `APIRouter`s.