head to head · open source
Milvus vs OpenSearch
Milvus has 46,153 GitHub stars, 4,256 forks, 1,405 open issues and last shipped today. OpenSearch has 13,727 stars, 2,957 forks, 3,167 open issues and last shipped today. Milvus leads on adoption by 236% (46,153 vs 13,727 stars). Milvus is written in Go under Apache-2.0; OpenSearch is written in Java under Apache-2.0. Milvus has attracted 9% as many forks as stars, OpenSearch 22%. Milvus was the more recently maintained of the two, and both are self-hostable with no licence fee.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
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Side by side
| Milvus | OpenSearch | |
|---|---|---|
| GitHub stars | ★ 46K | ★ 14K |
| License | Apache-2.0 | Apache-2.0 |
| Written in | Go | Java |
| Last push | 2026-09-18 | 2026-09-18 |
| Forks | ⑂ 4.3K | ⑂ 3.0K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Milvus if
- You weight community size — 46K stars and counting
- You want the Apache-2.0 license terms
- Your stack matches Go
- You value the larger contributor base for long-term maintenance
pick OpenSearch if
- You want the OpenSearch feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches Java
- You evaluated both and OpenSearch fits your workflow better
About Milvus
Milvus is a high performance, cloud native vector database written in Go and C++, designed to power AI applications by efficiently storing, indexing, and searching large scale unstructured data such as text, images, and multi modal embeddings. It implements hardware accelerated approximate nearest neighbor (ANN) search using algorithms like HNSW, FAISS, and DiskANN, and supports both real time streaming updates and batch ingestion. Milvus lives in the GenAI infrastructure ecosystem, serving as the persistent storage and retrieval layer for embedding based workloads including RAG, recommendation, and image search.…
read the full Milvus overview →
About OpenSearch
OpenSearch is an open source, distributed, and RESTful search engine, described in its README as an enterprise grade search and observability suite. It lives in the open source search and analytics ecosystem, is written in Java, and is licensed under Apache 2.0. The project states that it includes certain Apache licensed Elasticsearch code from Elasticsearch B.V., and that OpenSearch is a registered trademark of LF Projects, LLC.
read the full OpenSearch overview →
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Frequently asked questions
Is Milvus or OpenSearch more popular?
Milvus has 46,153 GitHub stars and OpenSearch has 13,727. Milvus has the larger community by that measure.
Are Milvus and OpenSearch free?
Both are open source. Milvus is licensed under Apache-2.0 and OpenSearch under Apache-2.0. Neither carries a licence fee.
What is the difference between Milvus and OpenSearch?
Milvus is written in Go and OpenSearch in Java. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, Milvus or OpenSearch?
Choose Milvus if you want the larger community (46,153 stars) or its Apache-2.0 licence terms. Choose OpenSearch if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.