Elasticsearch: The 70k-Star Search Engine That Went SSPL and Forked Into OpenSearch — A License Deep Dive
Elasticsearch powered search and logging under Apache 2.0 for a decade. Then in January 2021 Elastic went SSPL/Elastic License, and AWS forked the last open version into OpenSearch. This deep dive covers the relicensing, the fork, API compatibility, the AGPL olive branch, vector search divergence, real costs, data sovereignty, and how to choose in 2026.