> ## 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.

# Index Pipeline Stages

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-ai/reference/index-pipeline-stages/overview

[mintlify link]: https://doc.lucidworks.com/docs/4/fusion-ai/reference/index-pipeline-stages/overview

[old doc.lw link]: https://doc.lucidworks.com/fusion-ai/4.2/545

Index Pipeline stages are used to create and modify [PipelineDocument objects](https://javadoc.lucidworks.com/fusion-pipeline-javadocs/4.2/com/lucidworks/apollo/common/pipeline/PipelineDocument.html). Use the [Index Workbench](/docs/4/fusion-server/concepts/indexing/datasources/index-workbench) to configure stages in a pipeline and preview the results.

<LwTemplate />

See these reference topics for details about each index pipeline stage:

* [Format Signals](/docs/4/fusion-ai/reference/index-pipeline-stages/signal-formatter-index-stage)
* [OpenNLP NER Extraction](/docs/4/fusion-ai/reference/index-pipeline-stages/opennlp-ner-extractor-index-stage)
* [Machine Learning](/docs/4/fusion-ai/reference/index-pipeline-stages/machine-learning-index-stage)
* [NLP Annotator](/docs/4/fusion-ai/reference/index-pipeline-stages/nlp-annotator-index-stage)