# Query Engine

A query engine serves as an end-to-end pipeline enabling users to ask questions about their data. It receives a natural language query and furnishes a response, accompanied by relevant context information retrieved and passed to the LLM (Large Language Model).

<figure><img src="https://662370747-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F3VoWwSsyrEg0DEvIIjv9%2Fuploads%2Fgit-blob-1e4bde6915eda91d34829f98b1049736330f101b%2Fimage%20(3)%20(1)%20(1)%20(1)%20(1)%20(1)%20(1)%20(2)%20(1).png?alt=media" alt=""><figcaption></figcaption></figure>

## Inputs

* Vector Store Retriever
* [Response Synthesizer](https://tailwindsdocs.innovativesol.com/readme/chatflows/llamaindex/response-synthesizer)

## Parameters

| Name                    | Description                                                         |
| ----------------------- | ------------------------------------------------------------------- |
| Return Source Documents | To return citations/sources that were used to build up the response |

## Outputs

| Name        | Description                   |
| ----------- | ----------------------------- |
| QueryEngine | Final node to return response |