> ## Documentation Index
> Fetch the complete documentation index at: https://docs.langchain.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Store integrations

> Integrate with stores using LangChain Python.

## Overview

LangChain provides a key-value store interface for storing and retrieving data by key. The key-value store interface in LangChain is primarily used for caching [embeddings](/oss/python/integrations/embeddings).

## Interface

All [`BaseStores`](https://reference.langchain.com/python/langchain-core/stores/BaseStore) support the following interface:

* `mget(key: Sequence[str]) -> List[Optional[bytes]]`: get the contents of multiple keys, returning `None` if the key does not exist
* `mset(key_value_pairs: Sequence[Tuple[str, bytes]]) -> None`: set the contents of multiple keys
* `mdelete(key: Sequence[str]) -> None`: delete multiple keys
* `yield_keys(prefix: Optional[str] = None) -> Iterator[str]`: yield all keys in the store, optionally filtering by a prefix

<Note>
  Base stores are designed to work **multiple** key-value pairs at once for efficiency. This saves on network round-trips and may allow for more efficient batch operations in the underlying store.
</Note>

## Built-in stores for local development

<Columns cols={2}>
  <Card title="InMemoryByteStore" icon="link" href="/oss/python/integrations/stores/in_memory" arrow="true" cta="View guide" />

  <Card title="LocalFileStore" icon="link" href="/oss/python/integrations/stores/file_system" arrow="true" cta="View guide" />
</Columns>

## Custom stores

You can also implement your own custom store by extending the [`BaseStore`](https://reference.langchain.com/python/langchain-core/stores/BaseStore) class. See the [store interface documentation](https://reference.langchain.com/python/langchain-core/stores/BaseStore) for more details.

## All key-value stores

<div class="integration-downloads-table">
  | Integration                                                                                  | Downloads                                                                                                                                                                                                                                                      |
  | :------------------------------------------------------------------------------------------- | :------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
  | [`ElasticsearchEmbeddingsCache`](/oss/python/integrations/stores/elasticsearch)              | <span data-sort-value="326000"><a href="https://pypi.org/project/langchain-elasticsearch/" target="_blank">  <img src="https://static.pepy.tech/badge/langchain-elasticsearch/month" alt="Downloads per month" noZoom class="rounded not-prose" /></a></span>  |
  | [`AstraDBByteStore`](/oss/python/integrations/stores/astradb)                                | <span data-sort-value="226000"><a href="https://pypi.org/project/langchain-astradb/" target="_blank">  <img src="https://static.pepy.tech/badge/langchain-astradb/month" alt="Downloads per month" noZoom class="rounded not-prose" /></a></span>              |
  | [`M3Store`](https://github.com/skynetcmd/m3-memory/blob/main/docs/integrations/LANGCHAIN.md) | <span data-sort-value="25000"><a href="https://pypi.org/project/m3-memory/" target="_blank">  <img src="https://static.pepy.tech/badge/m3-memory/month" alt="Downloads per month" noZoom class="rounded not-prose" /></a></span>                               |
  | [`HindsightStore`](https://docs.hindsight.vectorize.io/sdks/integrations/langgraph)          | <span data-sort-value="2000"><a href="https://pypi.org/project/hindsight-langgraph/" target="_blank">  <img src="https://static.pepy.tech/badge/hindsight-langgraph/month" alt="Downloads per month" noZoom class="rounded not-prose" /></a></span>            |
  | [`BigtableByteStore`](/oss/python/integrations/stores/bigtable)                              | <span data-sort-value="440"><a href="https://pypi.org/project/langchain-google-bigtable/" target="_blank">  <img src="https://static.pepy.tech/badge/langchain-google-bigtable/month" alt="Downloads per month" noZoom class="rounded not-prose" /></a></span> |
  | [`TypeDBStore`](https://typedb.com/docs)                                                     | <span data-sort-value="80"><a href="https://pypi.org/project/langgraph-store-typedb/" target="_blank">  <img src="https://static.pepy.tech/badge/langgraph-store-typedb/month" alt="Downloads per month" noZoom class="rounded not-prose" /></a></span>        |
  | [`InspeximusStore`](https://dancenitra.github.io/inspeximus/)                                | <span data-sort-value="0"><a href="https://pypi.org/project/langgraph-store-inspeximus/" target="_blank">  <img src="https://static.pepy.tech/badge/langgraph-store-inspeximus/month" alt="Downloads per month" noZoom class="rounded not-prose" /></a></span> |
  | [`InMemoryByteStore`](/oss/python/integrations/stores/in_memory)                             | <span data-sort-value="-1">N/A</span>                                                                                                                                                                                                                          |
  | [`LocalFileStore`](/oss/python/integrations/stores/file_system)                              | <span data-sort-value="-1">N/A</span>                                                                                                                                                                                                                          |
</div>

***

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