Without a data validation system, you would have to do all the checks by hand, in code.

These features are what Marshmallow was built to provide. It is a great library, and I have used it a lot before.

# External Links

**FastAPI** has a great community constantly growing.

There are many posts, articles, tools, and projects, related to **FastAPI**.

You could easily use a search engine or video platform to find many resources related to FastAPI.

/// info

Before, this page used to list links to external articles.

async def update_item(item_id: str):
    if item_id != "plumbus":
        raise HTTPException(
            status_code=403, detail="You can only update the item: plumbus"
        )

async def update_item(item_id: str):
    if item_id != "plumbus":
        raise HTTPException(
            status_code=403, detail="You can only update the item: plumbus"
        )

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.

As said in the section [Alternatives](alternatives.md){.internal-link target=_blank}:

<blockquote markdown="1">

**FastAPI** wouldn't exist if not for the previous work of others.

- kubeadm: fix a potential panic if kubeadm discovers an invalid, existing kubeconfig file ([#79165](https://github.com/kubernetes/kubernetes/pull/79165), [@neolit123](https://github.com/neolit123))
- kubeadm: treat non-fatal errors as warnings when doing reset ([#80862](https://github.com/kubernetes/kubernetes/pull/80862), [@drpaneas](https://github.com/drpaneas))

import com.google.common.annotations.J2ktIncompatible;
import java.io.Serializable;
import java.util.List;
import org.jspecify.annotations.Nullable;

/**
 * An ordering that treats all references as equals, even nulls.
 *
 * @author Emily Soldal
 */
@GwtCompatible
final class AllEqualOrdering extends Ordering<@Nullable Object> implements Serializable {

Up to now, you have been using common data types, like:

* `int`
* `float`
* `str`
* `bool`

But you can also use more complex data types.

And you will still have the same features as seen up to now:

* Great editor support.
* Data conversion from incoming requests.
* Data conversion for response data.
* Data validation.
* Automatic annotation and documentation.

## Other data types { #other-data-types }

 * </ul>
 *
 * <p>Consumers of this annotation include:
 *
 * <ul>
 *   <li>NullAway, which <a
 *       href="https://github.com/google/guava/issues/6126#issuecomment-1204399671">treats it
 *       identically to {@code Nullable}</a> as of version 0.9.9.
 *   <li><a href="https://developers.google.com/j2objc">J2ObjC</a>, maybe: It might no longer be

 * </ul>
 *
 * <p>Consumers of this annotation include:
 *
 * <ul>
 *   <li>NullAway, which <a
 *       href="https://github.com/google/guava/issues/6126#issuecomment-1204399671">treats it
 *       identically to {@code Nullable}</a> as of version 0.9.9.
 *   <li><a href="https://developers.google.com/j2objc">J2ObjC</a>, maybe: It might no longer be