---
title: Retrieval QA Chain
description: Documentation for the Retrieval QA Chain node in n8n, a workflow automation platform. Includes details of operations and configuration, and links to examples and credentials information.
---

# Retrieval QA Chain

The Retrieval QA Chain node allows you to answer a query based on document content indexed by a retriever.

On this page, you'll find the node parameters for the Retrieval QA Chain node, and links to more resources.

///  note  | Examples and templates
For usage examples and templates to help you get started, refer to n8n's [LangChain integrations](https://n8n.io/integrations/langchain/) page.
///	
## Node parameters

### Query

This is the prompt that the model will use.

```
What can you tell me about {{ $json.input }}
```
	
### Choose a mode

There are two modes:

* **Run Once for All Items**: this is the default. When your workflow runs, the chain will run once, regardless of how many input items there are.
* **Run Once for Each Item**: choose this if you want your chain to run for every input item.

## Related resources

View [example workflows and related content](https://n8n.io/integrations/langchain/) on n8n's website.

Refer to [LangChain's documentation on Retrieval QA](https://js.langchain.com/docs/modules/chains/popular/vector_db_qa) for more information about the service.

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