And we as developers keep improving the code as we find those bugs and as we implement new features (possibly adding new bugs too 😅).

### Small Errors Automatically Handled

When building web APIs with FastAPI, if there's an error in our code, FastAPI will normally contain it to the single request that triggered the error. 🛡

Docker and similar tools also use an **internal cache** when building the image, if a file hasn't changed since the last time building the container image, then it will **re-use the same layer** created the last time, instead of copying the file again and creating a new layer from scratch.

# Bigger Applications - Multiple Files

If you are building an application or a web API, it's rarely the case that you can put everything on a single file.

**FastAPI** provides a convenience tool to structure your application while keeping all the flexibility.

!!! info
    If you come from Flask, this would be the equivalent of Flask's Blueprints.

## An example file structure

Let's say you have a file structure like this:

```
.
├── app

---

"_If you're looking to learn one **modern framework** for building REST APIs, check out **FastAPI** [...] It's fast, easy to use and easy to learn [...]_"

"_We've switched over to **FastAPI** for our **APIs** [...] I think you'll like it [...]_"

---

"_If you're looking to learn one **modern framework** for building REST APIs, check out **FastAPI** [...] It's fast, easy to use and easy to learn [...]_"

"_We've switched over to **FastAPI** for our **APIs** [...] I think you'll like it [...]_"

**Source Code**: <a href="https://github.com/tiangolo/fastapi" target="_blank">https://github.com/tiangolo/fastapi</a>

---

FastAPI is a modern, fast (high-performance), web framework for building APIs with Python based on standard Python type hints.

The key features are:

Bauen Sie dazu zunächst die gesamte Dokumentation:

<div class="termy">

```console
// Verwenden Sie das Kommando „build-all“, das wird ein wenig dauern
$ python ./scripts/docs.py build-all

Building docs for: en
Building docs for: es
Successfully built docs for: es
```

</div>

**Source Code**: <a href="https://github.com/tiangolo/fastapi" target="_blank">https://github.com/tiangolo/fastapi</a>

---

FastAPI is a modern, fast (high-performance), web framework for building APIs with Python based on standard Python type hints.

The key features are:

    img: https://fastapi.tiangolo.com/img/sponsors/talkpython-v2.jpg
  - url: https://github.com/deepset-ai/haystack/
    title: Build powerful search from composable, open source building blocks
    img: https://fastapi.tiangolo.com/img/sponsors/haystack-fastapi.svg
  - url: https://databento.com/
    title: Pay as you go for market data
    img: https://fastapi.tiangolo.com/img/sponsors/databento.svg

但是当你完成翻译后，你可以像在线上展示一样测试所有内容，包括所有其他语言。

为此，首先构建所有文档：

<div class="termy">

```console
// Use the command "build-all", this will take a bit
$ python ./scripts/docs.py build-all

Building docs for: en
Building docs for: es
Successfully built docs for: es
```

</div>

这样会对每一种语言构建一个独立的文档站点，并最终把这些站点全部打包输出到 `./site/` 目录。



然后你可以使用命令 `serve` 来运行生成的站点：

<div class="termy">