> For the complete documentation index, see [llms.txt](https://docs.flowiseai.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.flowiseai.com/integrations/langchain/chains/conversational-retrieval-qa-chain.md).

# Conversational Retrieval QA Chain

A chain for performing question-answering tasks with a retrieval component.

<figure><img src="/files/oO8BfLtTAINe1yqUD83L" alt=""><figcaption></figcaption></figure>

## Definitions

**A retrieval-based question-answering chain**, which integrates with a retrieval component and allows you to configure input parameters and perform question-answering tasks.\
**Retrieval-Based Chatbots:** Retrieval-based chatbots are chatbots that generate responses by selecting pre-defined responses from a database or a set of possible responses. They "retrieve" the most appropriate response based on the input from the user.\
**QA (Question Answering):** QA systems are designed to answer questions posed in natural language. They typically involve understanding the question and searching for or generating an appropriate answer.

## Inputs

* [Language Model](/integrations/langchain/chat-models.md)
* [Vector Store Retriever](/integrations/langchain/vector-stores.md)
* [Memory (optional)](/integrations/langchain/memory.md)

## Parameters

| Name                    | Description                                                                                                                                               |
| ----------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Return Source Documents | To return citations/sources that were used to build up the response                                                                                       |
| System Message          | An instruction for LLM on how to answer query                                                                                                             |
| Chain Option            | Method on how to summarize, answer questions, and extract information from documents. Read [more](https://js.langchain.com/docs/modules/chains/document/) |

## Outputs

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