“Hybrid” covers several combinations: full-text (BM25) plus dense, sparse plus dense, or a text-match filter plus dense.
Combine signals
Pinecone gives you two ways to combine a keyword signal with a dense signal. Metadata filtering is a separate lever that composes with both: it narrows the candidate pool before ranking, so an out-of-scope document can’t compete for a result slot.
RRF is a fusion method, not a synonym for hybrid search. It’s one way to merge ranked lists, while “hybrid search” is the broader approach of combining signals. See Reciprocal rank fusion.
Choose an approach
For a new document or text workload, use the Documents API. Declare onestring field with both full_text_search and embed, so Pinecone indexes its text for full-text search and embeds it for semantic search. Then either filter an embed search with a text-match filter on that field, or run a text search and an embed search and fuse them with RRF. See Integrated embedding.
If you generate your own embeddings, declare a dense_vector field alongside one or more full-text string fields instead. See the full-text search example schemas.
For hybrid search on a legacy vector index, see Hybrid search on a single index and Hybrid search on separate indexes.