Today, we’re announcing metadata pre-filtering for Amazon S3 Vectors, which delivers higher recall on filtered queries by evaluating your metadata filter before the similarity search. You can filter on attributes such as tenant, category, status, or time, and pre-filtering adds prefix matching with $startsWith for paths, URLs, and hierarchical keys. Each vector carries up to 2 KB of filterable metadata, and a single query supports up to 100 filter constraints. There is no additional cost, no re-ingestion, and no change to your queries.
Most applications never search a whole index. They search the part of it that belongs to a particular user, account, or category, and they express that scope as a metadata filter. Semantic search, retrieval-augmented generation (RAG), and agentic applications all need the same thing from a filtered…
