OpenSearch.

TL;DR — OpenSearch supports vector search alongside classic BM25, filters, and analytics in one search engine.

What it is

It is useful for hybrid retrieval and observability-heavy deployments with existing OpenSearch estates.

Why it exists

If you already operate search clusters, adding vector retrieval in the same platform can reduce complexity.

Install

# enable k-NN/vector features in OpenSearch cluster
# create index mapping with vector field

Basic usage

# index docs with embeddings
# run hybrid BM25 + vector queries

When to use, when to skip

Use it when this category is a bottleneck in your agent stack and you want faster delivery with fewer custom components.

Skip it when your workload is tiny, requirements are fixed, or a plain provider SDK plus a few local functions is enough.

Alternatives

Compare with adjacent tools in the same AI Native category and choose based on interface style, deployment model (hosted vs self-hosted), and team familiarity.

Verified against project documentation, June 2026.