> ## Documentation Index
> Fetch the complete documentation index at: https://langchain-5e9cc07a-preview-change-1791323909-75c753a.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Retriever integrations

> Integrate with retrievers using LangChain JavaScript.

A [retriever](/oss/javascript/deepagents/retrieval) is an interface that returns documents given an unstructured query.
It is more general than a vector store.
A retriever does not need to be able to store documents, only to return (or retrieve) them.

Retrievers accept a string query as input and return a list of `Document` objects.

For specifics on how to use retrievers, see the [relevant how-to guides here](/oss/javascript/deepagents/retrieval).

Note that all [vector stores](/oss/javascript/integrations/vectorstores) can be [cast to retrievers](/oss/javascript/deepagents/retrieval).
Refer to the vector store [integration docs](/oss/javascript/integrations/vectorstores/) for available vector store retrievers.

## All retrievers

<div class="integration-downloads-table">
  | Retriever | Self-host | Cloud offering | Package | Downloads |
  | :- | :- | :- | :- | :- |
  | [`AWSKendraRetriever`](/oss/javascript/integrations/retrievers/kendra-retriever) | <span data-sort-value="0" /> | <span data-sort-value="0" /> | [`@langchain/aws`](https://www.npmjs.com/package/@langchain/aws) | <span data-sort-value="2940428"><a href="https://www.npmjs.com/package/@langchain/aws" target="_blank">  <img src="https://img.shields.io/npm/dm/@langchain/aws?style=flat-square&label=%20&" alt="Downloads per month" noZoom class="rounded not-prose" /></a></span> |
  | [`Knowledge bases for Amazon Bedrock`](/oss/javascript/integrations/retrievers/bedrock-knowledge-bases) | <span data-sort-value="0" /> | <span data-sort-value="0" /> | [`@langchain/aws`](https://www.npmjs.com/package/@langchain/aws) | <span data-sort-value="2940428"><a href="https://www.npmjs.com/package/@langchain/aws" target="_blank">  <img src="https://img.shields.io/npm/dm/@langchain/aws?style=flat-square&label=%20&" alt="Downloads per month" noZoom class="rounded not-prose" /></a></span> |
  | [`ExaRetriever`](/oss/javascript/integrations/retrievers/exa) | <span data-sort-value="0" /> | <span data-sort-value="0" /> | [`@langchain/exa`](https://www.npmjs.com/package/@langchain/exa) | <span data-sort-value="64698"><a href="https://www.npmjs.com/package/@langchain/exa" target="_blank">  <img src="https://img.shields.io/npm/dm/@langchain/exa?style=flat-square&label=%20&" alt="Downloads per month" noZoom class="rounded not-prose" /></a></span> |
  | [`PerplexitySearchRetriever`](/oss/javascript/integrations/retrievers/perplexity_search) | <span data-sort-value="0" /> | <span data-sort-value="0" /> | [`@langchain/perplexity`](https://www.npmjs.com/package/@langchain/perplexity) | <span data-sort-value="706"><a href="https://www.npmjs.com/package/@langchain/perplexity" target="_blank">  <img src="https://img.shields.io/npm/dm/@langchain/perplexity?style=flat-square&label=%20&" alt="Downloads per month" noZoom class="rounded not-prose" /></a></span> |
  | [`AlchemystRetriever`](https://getalchemystai.com/docs) | <span data-sort-value="0" /> | <span data-sort-value="0" /> | [`@alchemystai/langchain-js`](https://www.npmjs.com/package/@alchemystai/langchain-js) | <span data-sort-value="50"><a href="https://www.npmjs.com/package/@alchemystai/langchain-js" target="_blank">  <img src="https://img.shields.io/npm/dm/@alchemystai/langchain-js?style=flat-square&label=%20&" alt="Downloads per month" noZoom class="rounded not-prose" /></a></span> |
  | [`FoxNoseRetriever`](https://github.com/FoxNoseTech/langchain-foxnose-js#readme) | <span data-sort-value="1">❌</span> | <span data-sort-value="2">✅</span> | [`@foxnose/langchain`](https://www.npmjs.com/package/@foxnose/langchain) | <span data-sort-value="17"><a href="https://www.npmjs.com/package/@foxnose/langchain" target="_blank">  <img src="https://img.shields.io/npm/dm/@foxnose/langchain?style=flat-square&label=%20&" alt="Downloads per month" noZoom class="rounded not-prose" /></a></span> |
  | [`SourceyRetriever`](/oss/javascript/integrations/retrievers/sourcey) | <span data-sort-value="0" /> | <span data-sort-value="0" /> | [`langchain-sourcey`](https://www.npmjs.com/package/langchain-sourcey) | <span data-sort-value="17"><a href="https://www.npmjs.com/package/langchain-sourcey" target="_blank">  <img src="https://img.shields.io/npm/dm/langchain-sourcey?style=flat-square&label=%20&" alt="Downloads per month" noZoom class="rounded not-prose" /></a></span> |
  | [`Hyde`](/oss/javascript/integrations/retrievers/hyde) | <span data-sort-value="0" /> | <span data-sort-value="0" /> | | <span data-sort-value="-1">N/A</span> |
  | [`Self Querying with SAP HANA Cloud Vector Engine`](/oss/javascript/integrations/retrievers/self_query/hanavector_self_query) | <span data-sort-value="0" /> | <span data-sort-value="0" /> | | <span data-sort-value="-1">N/A</span> |
  | [`Time-weighted`](/oss/javascript/integrations/retrievers/time-weighted-retriever) | <span data-sort-value="0" /> | <span data-sort-value="0" /> | | <span data-sort-value="-1">N/A</span> |
</div>

<Info>
  If you'd like to contribute an integration, see [Contributing integrations](/oss/javascript/contributing#add-a-new-integration).
</Info>

***

<div className="source-links">
  <Callout icon="terminal-2">
    [Connect these docs](/use-these-docs) to your agent of choice via MCP for real-time answers.
  </Callout>

  <Callout icon="edit">
    [Edit this page on GitHub](https://github.com/langchain-ai/docs/edit/main/src/oss/javascript/integrations/retrievers/index.mdx) or [file an issue](https://github.com/langchain-ai/docs/issues/new/choose).
  </Callout>
</div>