Elasticsearch vs OpenSearch
Elasticsearch is the original search engine with vector search (kNN), analytics, and a vast ecosystem. OpenSearch is the community-driven fork, AWS-backed, with compatible APIs and additional features like observability and security plugins. Both handle full-text search and vector search; the choice often comes down to licensing and cloud provider preference.
Elasticsearch
Distributed search engine with vector capabilities
JavaElastic License 2.0traditional
Key Features
- kNN vector search
- Hybrid BM25 + vector queries
- Distributed & horizontally scalable
- Kibana visualizations
- Machine learning features
- Massive integration ecosystem
Pricing
Self-ManagedFree
Cloud (Standard)From ~$95/mo
EnterpriseCustom
Use Cases
Enterprise searchLog analytics + similarityE-commerce searchSecurity analytics
OpenSearch
Community-driven fork of Elasticsearch with vector search
JavaApache-2.0traditional
Key Features
- k-NN vector search (FAISS, NMSLIB)
- Hybrid text + vector search
- OpenSearch Dashboards
- SQL query support
- Anomaly detection
- AWS managed service available
Pricing
Self-ManagedFree
AWS ManagedPay-per-instance
Use Cases
Log & event analyticsEnterprise searchSecurity monitoringObservability + AI
Verdict
Elasticsearch for the established ecosystem and Elastic Cloud. OpenSearch for AWS-native deployments and fully open-source licensing.
Choose Elasticsearch if you need:
- ✓kNN vector search
- ✓Hybrid BM25 + vector queries
- ✓Distributed & horizontally scalable
Choose OpenSearch if you need:
- ✓k-NN vector search (FAISS, NMSLIB)
- ✓Hybrid text + vector search
- ✓OpenSearch Dashboards