"ketä", "kenessä", "kenestä", "keneen", "kenellä", "keneltä", "kenelle", "kenenä", "keneksi", "ketkä", "keiden", "ketkä", "keitä", "keissä", "keistä", "keihin", "keillä", "keiltä", "keille", "keinä", "keiksi", "mikä", "minkä", "minkä", "mitä", "missä", "mistä", "mihin", "millä", "miltä", "mille", "minä", "miksi", "mitkä", "joka", "jonka", "jota", "jossa", "josta", "johon", "jolla", "jolta", "jolle", "jona", "joksi", "jotka", "joiden", "joita", "joissa", "joista", "joihin", "joilla", "joilta", "joille",...

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  stars: 31799
  owner_login: mouredev
  owner_html_url: https://github.com/mouredev
- name: serve
  html_url: https://github.com/jina-ai/serve
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  owner_html_url: https://github.com/jina-ai
- name: HivisionIDPhotos
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  owner_login: Zeyi-Lin
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I will show you some of the main concepts you should probably keep in mind when deploying a **FastAPI** application (although most of it applies to any other type of web application).

//// tab | Python 3.8 non-Annotated

/// tip

Prefer to use the `Annotated` version if possible.

///

{* ../../docs_src/path_params_numeric_validations/tutorial002.py hl[7] *}

////

But keep in mind that if you use `Annotated`, you won't have this problem, it won't matter as you're not using the function parameter default values for `Query()` or `Path()`.

{* ../../docs_src/path_params_numeric_validations/tutorial002_an_py39.py *}

* You can then further modify the `response` before returning it.

{* ../../docs_src/middleware/tutorial001.py hl[8:9,11,14] *}

/// tip

Keep in mind that custom proprietary headers can be added <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers" class="external-link" target="_blank">using the 'X-' prefix</a>.

## Code size { #code-size }

This example might seem verbose. Keep in mind that we are mixing security, data models, utility functions and *path operations* in the same file.

But here's the key point.

The security and dependency injection stuff is written once.

        public int msecs;
        /**
         * The current hour (0-23).
         */
        public int hours;
        /**
         * The current minute (0-59).
         */
        public int mins;
        /**
         * The current second (0-59).
         */
        public int secs;
        /**
         * The current hundredth of a second (0-99).
         */
        public int hunds;

### `Query` as the default value or in `Annotated` { #query-as-the-default-value-or-in-annotated }

Keep in mind that when using `Query` inside of `Annotated` you cannot use the `default` parameter for `Query`.

Instead, use the actual default value of the function parameter. Otherwise, it would be inconsistent.

And as the `Response` can be used frequently to set headers and cookies, **FastAPI** also provides it at `fastapi.Response`.

///

## Custom Headers { #custom-headers }

Keep in mind that custom proprietary headers can be added <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers" class="external-link" target="_blank">using the 'X-' prefix</a>.