Retrievers
A retriever 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 Documents.
For specifics on how to use retrievers, see the relevant how-to guides here.
Note that all vector stores can be cast to retrievers.
Refer to the vector store integration docs for available vector store retrievers.
If you’d like to write your own retriever, see this how-to. If you’d like to contribute an integration, see Contributing integrations.