Elasticsearch vs OpenSearch

OpenSearch is an Apache 2.0-licensed fork of Elasticsearch 7.10, created by AWS after Elastic changed Elasticsearch's license from Apache 2.0 to SSPL/Elastic License. The projects have been diverging since 2021.

The License Split

Elastic changed Elasticsearch's license to prevent cloud providers (primarily AWS) from offering Elasticsearch as a managed service. AWS responded by forking Elasticsearch 7.10 into OpenSearch under the Apache 2.0 license. OpenSearch is now a Linux Foundation project with contributions from AWS, SAP, and others.

Diverging Features

Since the fork, both projects have added unique features:

Elasticsearch has invested in AI-powered search: ESRE (Elasticsearch Relevance Engine), ELSER (sparse retrieval model), and advanced vector search. Kibana continues to evolve with new visualization capabilities.

OpenSearch has added its own innovations: OpenSearch Dashboards, Piped Processing Language (PPL), k-NN search, and observability features. Security features that were previously commercial-only in Elasticsearch are included by default.

Learn about search architecture in system design concepts and interview preparation.

Compatibility

OpenSearch maintains backward compatibility with the Elasticsearch 7.10 API. Many Elasticsearch clients and tools work with OpenSearch, though newer Elasticsearch features and APIs are not available. As the projects diverge, compatibility will continue to decrease.

Cloud Options

AWS offers Amazon OpenSearch Service as a fully managed solution. Elastic offers Elastic Cloud on AWS, GCP, and Azure. Compare pricing carefully as the cost models differ.

The Bottom Line

Choose Elasticsearch when you need the latest AI-powered search features and the full Elastic Stack. Choose OpenSearch when you need Apache 2.0 licensing, AWS-native integration, or community governance. See system design guides.