Let's look at how we can make that work.

## pytest.mark.anyio { #pytest-mark-anyio }

If we want to call asynchronous functions in our tests, our test functions have to be asynchronous. AnyIO provides a neat plugin for this, that allows us to specify that some test functions are to be called asynchronously.

## HTTPX { #httpx }

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

## Asynchronous Code { #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" 📝.

Articles: English: - author: Balthazar Rouberol author_link: https://balthazar-rouberol.com link: https://blog.balthazar-rouberol.com/how-to-profile-a-fastapi-asynchronous-request title: How to profile a FastAPI asynchronous request - author: Stephen Siegert - Neon link: https://neon.tech/blog/deploy-a-serverless-fastapi-app-with-neon-postgres-and-aws-app-runner-at-any-scale title: Deploy a Serverless FastAPI App with Neon Postgres and AWS App Runner at any scale - author: Kurtis Pykes - NVIDIA...

En esta sección veremos cómo usar otros middlewares.

## Agregando middlewares ASGI

Como **FastAPI** está basado en Starlette e implementa la especificación <abbr title="Asynchronous Server Gateway Interface">ASGI</abbr>, puedes usar cualquier middleware ASGI.

Un middleware no tiene que estar hecho para FastAPI o Starlette para funcionar, siempre que siga la especificación ASGI.

///

/// tip

If you want to call `async` functions in your tests apart from sending requests to your FastAPI application (e.g. asynchronous database functions), have a look at the [Async Tests](../advanced/async-tests.md){.internal-link target=_blank} in the advanced tutorial.

///

## Separating tests { #separating-tests }

- **Flexible Text Processing**: Configurable converters and normalizers for text transformation
- **OpenSearch Integration**: Seamless integration with OpenSearch/Elasticsearch clusters
- **Asynchronous Operations**: Non-blocking suggestion requests with callback support
- **Index Management**: Automatic index creation, switching, and maintenance

Here's a little bit of that history.

## Alternatives { #alternatives }

I have been creating APIs with complex requirements for several years (Machine Learning, distributed systems, asynchronous jobs, NoSQL databases, etc), leading several teams of developers.

As part of that, I needed to investigate, test and use many alternatives.

The history of **FastAPI** is in great part the history of its predecessors.

///

### <a href="https://www.starlette.io/" class="external-link" target="_blank">Starlette</a> { #starlette }

Starlette is a lightweight <abbr title="The new standard for building asynchronous Python web applications">ASGI</abbr> framework/toolkit, which is ideal for building high-performance asyncio services.

It is very simple and intuitive. It's designed to be easily extensible, and have modular components.

## Servidores ASGI

Vamos nos aprofundar um pouco mais em detalhes.

FastAPI utiliza um padrão para construir frameworks e servidores web em Python chamado <abbr title="Asynchronous Server Gateway Interface">ASGI</abbr>. FastAPI é um framework web ASGI.

In this section we'll see how to use other middlewares.

## Adding ASGI middlewares { #adding-asgi-middlewares }

As **FastAPI** is based on Starlette and implements the <abbr title="Asynchronous Server Gateway Interface">ASGI</abbr> specification, you can use any ASGI middleware.

A middleware doesn't have to be made for FastAPI or Starlette to work, as long as it follows the ASGI spec.