The licensing story: Elastic vs Apache 2 — and why it matters more than you think
The Elastic vs OpenSearch split began in January 2021, when Elastic re-licensed Elasticsearch and Kibana from Apache 2 to the SSPL (Server Side Public License) and the Elastic License 2.0, citing concerns about large cloud providers (notably AWS) running Elasticsearch as a managed service without contributing back. AWS responded by forking Elasticsearch 7.10.2 under the Apache 2 license to create OpenSearch, committing to keep it fully open. This licensing story directly shapes your vendor risk today.
For self-hosted Elasticsearch, the practical split is: core full-text search, aggregations, basic kNN vector search, and BM25 are under the Apache 2 license (or the Elastic Source Available License, which allows most non-SaaS commercial use). But ELSER (the sparse learned encoder that powers semantic search without external embeddings), semantic_text automatic embedding, ML nodes, and the full AI Search stack are under the Elastic License 2.0 — which prohibits providing the software to third parties as a service. If you are building a search product and reselling it to customers, Elastic License creates legal friction. If you are using Elasticsearch internally, Elastic License is a non-issue for most organizations.
OpenSearch carries no ML feature gating. Every vector search feature, the neural search pipeline, sparse neural retrieval, hybrid search with normalization processors — all Apache 2. No per-feature tier unlocking, no license check at ML node startup. If open licensing is a hard requirement for your architecture (government procurement, open-source product, concerns about long-term vendor lock-in), OpenSearch or Typesense are your options.
Typesense uses Apache 2 for the server binary; some client libraries moved to the Business Source License (BSL 1.1) in late 2024, which converts to Apache 2 after four years. BSL restricts using the client library itself to provide a competing search-as-a-service product, but does not restrict building applications on top of Typesense. For almost all application teams, Typesense licensing is clean.
The practical bottom line: if you are an internal enterprise team self-hosting search, Elastic License is typically not a barrier and you can use ELSER freely. If you are building a product that embeds search as a feature and sells it to customers, the Apache 2 stack (OpenSearch or Typesense) removes legal ambiguity. If you are a startup on AWS, OpenSearch + managed service is the path of least friction — you avoid the Elastic License complexity and integrate natively with SageMaker and Bedrock for embeddings.
One more licensing angle: Elastic has also changed the licensing of Elasticsearch multiple times since 2018 (first to a dual license in 2018, then SSPL in 2021, then Elastic License 2.0). Organizations burned by the 2021 change reason that the license could change again. OpenSearch, governed by AWS with Apache 2 as the stated permanent license, and Typesense, a small focused company with a clean server license, both carry lower re-licensing risk.