OpenSearch
apache-2.0 with no licence anxiety, and serverless finally scales to zero
the safe institutional choice on aws — genuinely apache-2.0, with faiss and lucene engines, and the always-on cost floor finally removed.
opensearch is apache-2.0 throughout, which in a category with this many licence traps is worth real money in avoided legal review. the k-nn plugin supports hnsw and ivf across both faiss and lucene engines, plus disk-based modes and binary and byte quantization.
the important 2026 change is on the serverless side. previously the smallest classic collection carried a two-unit minimum that cost hundreds of dollars a month even at zero traffic, which made 'serverless' something of a misnomer. nextgen collections have no minimum and scale to zero after ten minutes idle.
the description above is ours, condensed from the ranking. pricing moves — check it on the vendor's own page before you rely on it.
- category
- vector databases
- pricing
- free self-hosted; serverless billed per OCU-hour
- website
- opensearch.org
the safe institutional choice on aws — genuinely apache-2.0, with faiss and lucene engines, and the always-on cost floor finally removed.
we researched this category against vendors' own pricing pages and licence files. that is where this line comes from — not from the vendor, and not from anything they paid for.