### What is a Process

The word **process** is normally used in a more specific way, only referring to the thing that is running in the operating system (like in the last point above):

* A particular program while it is **running** on the operating system.

I have been avoiding the creation of a new framework for several years. First I tried to solve all the features covered by **FastAPI** using many different frameworks, plug-ins, and tools.

!!! check "vérifier"
    Donc, avec ces mêmes déclarations de type Python, **FastAPI** vous fournit de la validation de données.

    Notez que l'erreur mentionne le point exact où la validation n'a pas réussi.

    Ce qui est incroyablement utile au moment de développer et débugger du code qui interagit avec votre API.

## Documentation

You would probably get a cloud server (a virtual machine) or something similar, and it would have a <abbr title="That doesn't change">fixed</abbr> **public IP address**.

In the DNS server(s) you would configure a record (an "`A record`") to point **your domain** to the public **IP address of your server**.

You would probably do this just once, the first time, when setting everything up.

!!! tip

```Python hl_lines="2"
{!../../../docs_src/python_types/tutorial001.py!}
```

### Edit it

It's a very simple program.

But now imagine that you were writing it from scratch.

At some point you would have started the definition of the function, you had the parameters ready...

But then you have to call "that method that converts the first letter to upper case".

```Python hl_lines="3"
{!../../../docs_src/first_steps/tutorial001.py!}
```

Here the `app` variable will be an "instance" of the class `FastAPI`.

This will be the main point of interaction to create all your API.

### Step 3: create a *path operation*

#### Path

"Path" here refers to the last part of the URL starting from the first `/`.

So, in a URL like:

```

Pendant que vous êtes assis à table, en attendant que les burgers 🍔 soient prêts, vous pouvez passer ce temps à admirer à quel point votre crush 😍 est géniale, mignonne et intelligente ✨😍✨.

    And this path operation will:

    * Send the invoice to the client.
    * Collect the money from the client.
    * Send a notification back to the API user (the external developer), as a callback.
        * At this point is that the API will somehow send a POST request to the
            external API with the notification of the invoice event
            (e.g. "payment successful").
    """

```Python hl_lines="2"
{!../../../docs_src/python_types/tutorial001.py!}
```

### Limitations

C'est un programme très simple.

Mais maintenant imaginez que vous l'écriviez de zéro.

À un certain point vous auriez commencé la définition de la fonction, vous aviez les paramètres prêts.

Mais vous aviez besoin de "cette méthode qui convertit la première lettre en majuscule".

* **Asynchronous Code**
* **`async` and `await`**
* **Coroutines**

## Asynchronous Code

Asynchronous code just means that the language 💬 has a way to tell the computer / program 🤖 that at some point in the code, it 🤖 will have to wait for *something else* to finish somewhere else. Let's say that *something else* is called "slow-file" 📝.