[AccessHeadersJava]: https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/AccessHeaders.java
 [AccessHeadersKotlin]: https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/kt/AccessHeaders.kt
 [PostStringJava]: https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/PostString.java

### OpenAPI-specific `examples` { #openapi-specific-examples }

Since before **JSON Schema** supported `examples` OpenAPI had support for a different field also called `examples`.

	n.activeConnections--
	if n.firstToDisconnect.IsZero() {
		n.RXSample = atomic.LoadUint64(&n.RX)
		n.firstToDisconnect = time.Now()
	}
}

func (n *netPerfRX) ActiveConnections() uint64 {
	n.RLock()
	defer n.RUnlock()
	return n.activeConnections
}

func (n *netPerfRX) Reset() {
	n.Lock()
	defer n.Unlock()
	n.RX = 0
	n.RXSample = 0
	n.lastToConnect = time.Time{}

### Example Tools to Run at Startup { #example-tools-to-run-at-startup }

Some examples of the tools that can do this job are:

* Docker
* Kubernetes
* Docker Compose
* Docker in Swarm Mode
* Systemd
* Supervisor
* Handled internally by a cloud provider as part of their services
* Others...

I'll give you more concrete examples in the next chapters.

## Restarts { #restarts }

  stars: 1209
  owner_login: slackapi
  owner_html_url: https://github.com/slackapi
- name: bedrock-chat
  html_url: https://github.com/aws-samples/bedrock-chat
  stars: 1199
  owner_login: aws-samples
  owner_html_url: https://github.com/aws-samples
- name: fastapi_production_template
  html_url: https://github.com/zhanymkanov/fastapi_production_template
  stars: 1182
  owner_login: zhanymkanov

Like `item.model_dump(exclude_unset=True)`.

/// info

In Pydantic v1 the method was called `.dict()`, it was deprecated (but still supported) in Pydantic v2, and renamed to `.model_dump()`.

The examples here use `.dict()` for compatibility with Pydantic v1, but you should use `.model_dump()` instead if you can use Pydantic v2.

///

You can declare extra information in `Field`, `Query`, `Body`, etc. And it will be included in the generated JSON Schema.

You will learn more about adding extra information later in the docs, when learning to declare examples.

/// warning

Extra keys passed to `Field` will also be present in the resulting OpenAPI schema for your application.

It helps a lot during **development**, but you **shouldn't** use it in **production**.

///

## Deployment Concepts { #deployment-concepts }

These examples run the server program (e.g Uvicorn), starting **a single process**, listening on all the IPs (`0.0.0.0`) on a predefined port (e.g. `80`).

{* ../../docs_src/dependencies/tutorial011_an_py39.py hl[22] *}

/// tip

All this might seem contrived. And it might not be very clear how is it useful yet.

These examples are intentionally simple, but show how it all works.

In the chapters about security, there are utility functions that are implemented in this same way.

You just pass it to `Depends` and **FastAPI** knows how to do the rest.

///

## Share `Annotated` dependencies { #share-annotated-dependencies }

In the examples above, you see that there's a tiny bit of **code duplication**.

When you need to use the `common_parameters()` dependency, you have to write the whole parameter with the type annotation and `Depends()`:

```Python