When you run `fastapi dev`, it will run on development mode.

By default, it will have **auto-reload** enabled, so it will automatically reload the server when you make changes to your code. This is resource intensive and could be less stable than without it, you should only use it for development.

By default it will listen on the IP address `127.0.0.1`, which is the IP for your machine to communicate with itself alone (`localhost`).

## `fastapi run`

    val durationsPerTestProject = projectDurations.groupBy({ it.testProject }, { it.scenarioDurations })
    durationsPerTestProject.forEach { (key, value) -> if (value.size != 1) throw IllegalArgumentException("More than one scenario split for test project $key: $projectDurations") }
    return durationsPerTestProject
        .mapValues { (_, durations) -> durations.flatten().map { it.scenario } }
}

![ReDoc](https://fastapi.tiangolo.com/img/index/index-06-redoc-02.png)

### Just Modern Python

It's all based on standard **Python type** declarations (thanks to Pydantic). No new syntax to learn. Just standard modern Python.

# Extra Models

Continuing with the previous example, it will be common to have more than one related model.

This is especially the case for user models, because:

* The **input model** needs to be able to have a password.
* The **output model** should not have a password.
* The **database model** would probably need to have a hashed password.

!!! danger
    Never store user's plaintext passwords. Always store a "secure hash" that you can then verify.

    {!> ../../../docs_src/dependencies/tutorial001.py!}
    ```

That's it.

**2 lines**.

And it has the same shape and structure that all your *path operation functions* have.

You can think of it as a *path operation function* without the "decorator" (without the `@app.get("/some-path")`).

And it can return anything you want.

In this case, this dependency expects:

- In the event that more than one IngressClass is designated "default", the DefaultIngressClass admission controller will choose one rather than fail. ([#110974](https://github.com/kubernetes/kubernetes/pull/110974), [@kidddddddddddddddddddddd](https://github.com/kidddddddddddddddddddddd)) [SIG Network]

Because `Annotated` can have more than one metadata annotation, you could now even use the same function with other tools, like <a href="https://typer.tiangolo.com/" class="external-link" target="_blank">Typer</a>. 🚀

## Add more validations

  the correct number of rules, rather than being off by one.
  
  Fixed multiple iptables proxy regressions introduced in 1.22:
  
    - When using Services with SessionAffinity, client affinity for an
      endpoint now gets broken when that endpoint becomes non-ready
      (rather than continuing until the endpoint is fully deleted).
  

- Support more than 100 disk mounts on Windows (#105673, @andyzhangx) [SIG Storage and Windows]
- The --leader-elect* CLI args are now honored correctly in scheduler. (#106130, @Huang-Wei) [SIG Scheduling]
- The kube-proxy sync_proxy_rules_iptables_total metric now gives
  the correct number of rules, rather than being off by one.
  

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