> ## 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.

# Template Expressions

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/reference/template-expressions/overview

[mintlify link]: https://doc.lucidworks.com/docs/4/fusion-server/reference/template-expressions/overview

[old doc.lw link]: https://doc.lucidworks.com/fusion/5.9/10911

Template expressions are a way to map field values in a document. They are used to configure some Fusion pipeline stage and messaging services. When the value of a configuration parameter is a template expression, that expression is dynamically evaluated at runtime by the [StringTemplate](https://github.com/antlr/stringtemplate4/blob/master/doc/cheatsheet.md) library.

<LwTemplate />

Fusion template expressions are delimited by angle bracket characters `<` and `>`.
The expression consists of the name of a variable in the scope of that component.

Since these variables are Java objects, if object **foo** of type Foo has a field named **bar**, the expression **`<foo.bar>`** will evaluate to the string representation of the contents of field **bar**.

For example, given a PipelineDocument where a field named **title** has a value of **Star Wars**, the template expression `<doc.title>` evaluates to **Star Wars**.

See the reference guide for [index pipeline stage](/docs/4/fusion-server/reference/template-expressions/index-pipeline-variables), [query pipeline stage](/docs/4/fusion-server/reference/template-expressions/query-pipeline-variables), and [messaging service](/docs/4/fusion-server/reference/template-expressions/messaging-service-variables) template expression variables.