> ## Documentation Index
> Fetch the complete documentation index at: https://doc.lucidworks.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Building Applications

export const LwTemplate = ({title = "Key questions to get you started", icon = "sparkles", cta = "Powered by Agent Studio", linkHref = "https://lucidworks.com/demo/?utm_source=docs&utm_medium=referral&utm_campaign=docs_cta_ai"}) => {
  const [isLoaded, setIsLoaded] = useState(false);
  useEffect(() => {
    const timer = setTimeout(() => {
      setIsLoaded(true);
    }, 500);
    return () => clearTimeout(timer);
  }, []);
  return <div className="lw-template-container">
      <Card title={title} icon={icon}>
        {isLoaded && <span dangerouslySetInnerHTML={{
    __html: `<lw-template id="a029c1a9-28be-427e-b0e1-5d918920246a"></lw-template
            >`
  }} />}
        <Link href={linkHref} className="agent-studio-link text-left text-gray-600 gap-2 dark:text-gray-400 text-sm font-medium flex flex-row items-center hover:text-primary dark:hover:text-primary-light group-hover:text-primary group-hover:dark:text-primary-light">Powered by Lucidworks Agent Studio</Link>
      </Card>
    </div>;
};

[localhost link]: http://localhost:3000/docs/4/fusion-server/concepts/querying/apps/overview

[mintlify link]: https://doc.lucidworks.com/docs/4/fusion-server/concepts/querying/apps/overview

[old doc.lw link]: https://doc.lucidworks.com/fusion-server/4.2/180

Ultimately, Fusion Server is the back end for your search applications.

<LwTemplate />

[Fusion App Studio](/docs/4/app-studio/overview) is a tool for developing a search interface from within the Fusion workspace, using a simple configuration wizard and an integrated code editor. You can set up a simple search interface in just minutes, and then customize it to suit your organization.

If you develop your own search application from scratch, it must make calls to Fusion’s [REST API](/docs/4/fusion-server/reference/api/overview) in order to retrieve search results or perform other actions, such as uploading blobs, modifying user roles, or sending messages.

Certain features require configuration on the Fusion back end before you can surface them in your application:

* [autocomplete](/docs/4/fusion-server/concepts/querying/apps/autocomplete)
* [faceting](/docs/4/fusion-server/concepts/querying/apps/faceting)
* [synonyms](/docs/4/fusion-server/concepts/querying/apps/synonyms-files)
* [stopwords](/docs/4/fusion-server/concepts/querying/apps/stopwords-files)

If you are using [Fusion AI](/docs/4/fusion-ai/overview), then your application can also send [signals](/docs/4/fusion-ai/concepts/signals-and-aggregations/signals/overview) to Fusion and retrieve [recommendations](/docs/4/fusion-ai/concepts/boosting/overview) to personalize each user’s search experience.