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Reranking is used as part of a two-stage vector retrieval process to improve the quality of results. You first query an index for a given number of relevant results, and then you send the query and results to a reranking model. The reranking model scores the results based on their semantic relevance to the query and returns a new, more accurate ranking. This approach is one of the simplest methods for improving quality in retrieval augmented generation (RAG) pipelines. Pinecone provides hosted reranking models so it’s easy to manage two-stage vector retrieval on a single platform. You can use a hosted model to rerank results as an integrated part of a query, or you can use a hosted model or external model to rerank results as a standalone operation.
To run through this guide in your browser, see the Rerank example notebook.

Integrated reranking

To rerank initial results as an integrated part of a query, without any extra steps, use the Search with text operation with the rerank parameter, including the hosted reranking model you want to use, the number of reranked results to return, and the fields to use for reranking, if different than the main query. For example, the following code searches for the 3 records most semantically related to a query text and uses the hosted bge-reranker-v2-m3 model to rerank the results and return only the 2 most relevant documents:
The response looks as follows. For each hit, the _score represents the relevance of a document to the query, normalized between 0 and 1, with scores closer to 1 indicating higher relevance.

Standalone reranking

To rerank initial results as a standalone operation, use the Rerank results operation with the hosted reranking model you want to use, the query results and the query, the number of ranked results to return, the field to use for reranking, and any other model-specific parameters. For example, the following code uses the hosted bge-reranker-v2-m3 model to rerank the values of the documents.chunk_text fields based on their relevance to the query and return only the 2 most relevant documents, along with their score:
The response looks as follows. For each hit, the _score represents the relevance of a document to the query, normalized between 0 and 1, with scores closer to 1 indicating higher relevance.

Rerank results on the default field

To rerank search results, specify a supported reranking model, and provide documents and a query as well as other model-specific parameters. By default, Pinecone expects the documents to be in the documents.text field. For example, the following request uses the bge-reranker-v2-m3 reranking model to rerank the values of the documents.text field based on their relevance to the query, "The tech company Apple is known for its innovative products like the iPhone.".
With truncate set to "END", the input sequence (query + document) is truncated at the token limit (1024); to return an error instead, you’d set truncate to "NONE" or leave the parameter out.
The returned object contains documents with relevance scores:
Normalized between 0 and 1, the score represents the relevance of a passage to the query, with scores closer to 1 indicating higher relevance.

Rerank results on a custom field

To rerank results on a field other than documents.text, provide the rank_fields parameter to specify the fields on which to rerank.
bge-reranker-v2-m3 and pinecone-rerank-v0 support only a single rerank field. cohere-rerank-4-fast supports multiple rerank fields, ranked based on the order of the fields specified.
For example, the following request reranks documents based on the values of the documents.my_field field:

Reranking models

Pinecone hosts these reranking models: Each model’s page lists the parameters it accepts and its specs, such as max tokens, max documents per request, and plan. To compare the models, see the model gallery.
To understand how cost is calculated for reranking, see Reranking cost. To get model details via the API, see List models and Describe a model.