cfa
cfd
cfolks.pl
cg
ch
ch.eu.org
ch.it
ch.trendhosting.cloud
chambagri.fr
championship.aero
chanel
channel
channelsdvr.net
charity
charter.aero
chase
chat
cheap
cheap.jp
cherkassy.ua
cherkasy.ua
chernigov.ua
chernihiv.ua
chernivtsi.ua
chernovtsy.ua
chiba.jp
chicappa.jp
chichibu.saitama.jp
chieti.it
chigasaki.kanagawa.jp

...
```

#### What is OpenAPI for { #what-is-openapi-for }

The OpenAPI schema is what powers the two interactive documentation systems included.

And there are dozens of alternatives, all based on OpenAPI. You could easily add any of those alternatives to your application built with **FastAPI**.

This decoupling of parts, and being a "microframework" that could be extended to cover exactly what is needed was a key feature that I wanted to keep.

Given the simplicity of Flask, it seemed like a good match for building APIs. The next thing to find was a "Django REST Framework" for Flask.

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

as well say that "I see what I eat" is the same thing as "I eat
what I see"!'

  `You might just as well say,' added the March Hare, `that "I
like what I get" is the same thing as "I get what I like"!'

  `You might just as well say,' added the Dormouse, who seemed to
be talking in his sleep, `that "I breathe when I sleep" is the
same thing as "I sleep when I breathe"!'

      description: Tell us what happens
    validations:
      required: true
  - type: textarea
    id: expected-behavior
    attributes:
      label: Expected Behavior
      description: Tell us what should happen
    validations:
      required: true
  - type: textarea
    id: context
    attributes:
      label: Context (optional)
      description: |
        How has this issue affected you? What are you trying to accomplish?

You could create an API with a *path operation* that could trigger a request to an *external API* created by someone else (probably the same developer that would be *using* your API).

The process that happens when your API app calls the *external API* is named a "callback". Because the software that the external developer wrote sends a request to your API and then your API *calls back*, sending a request to an *external API* (that was probably created by the same developer).

        a full-time Guava team member. [Feedback](https://stackoverflow.com/a/4543114) from our
        users indicates that they really appreciate Guava's high power-to-weight ratio. It's
        important to us to keep Guava as easy to use and understand as we can. That means boiling
        features down to compact but powerful abstractions, and controlling feature bloat carefully.

  - type: textarea
    attributes:

```

////

The last `CommonQueryParams`, in:

```Python
... Depends(CommonQueryParams)
```

...is what **FastAPI** will actually use to know what is the dependency.

It is from this one that FastAPI will extract the declared parameters and that is what FastAPI will actually call.

---

In this case, the first `CommonQueryParams`, in:

//// tab | Python 3.9+

```Python

### FastAPI Data Filtering { #fastapi-data-filtering }

Now, for FastAPI, it will see the return type and make sure that what you return includes **only** the fields that are declared in the type.

  - type: textarea
    attributes:
      label: 1. What are you trying to do?
    validations:
      required: true

  - type: textarea
    attributes:
      label: 2. What's the best code you can write to accomplish that without the new feature?
    validations:
      required: true

  - type: textarea
    attributes:
      label: 3. What would that same code look like if we added your feature?
    validations: