# OpenSearch

> search engine, fork of Elasticsearch

**Wikidata**: [Q106497646](https://www.wikidata.org/wiki/Q106497646)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/OpenSearch_(software))  
**Source**: https://4ort.xyz/entity/opensearch

## Summary
OpenSearch is a free, open-source search engine and analytics suite that is a fork of Elasticsearch. It is a distributed, document-oriented search platform written in Java that uses the Apache Lucene library and is licensed under the Apache License 2.0.

## Key Facts
- OpenSearch is a fork of Elasticsearch and was started in April 2021.  
- The project is licensed under the Apache Software License 2.0.  
- OpenSearch is implemented in the Java programming language.  
- OpenSearch uses the Apache Lucene search library for full-text queries.  
- OpenSearch is classified as a document-oriented database management system, a distributed database management system, a search engine, and free and open-source software.  
- The project website for documentation is https://opensearch.org/docs/latest/opensearch/index/ (English).  
- The source code repository is hosted at https://github.com/opensearch-project/OpenSearch and the GitHub organization is opensearch-project.  
- Initial public milestones: 1.0.0 Beta 1 announced 2021-05-13; 1.0.0 Release Candidate 1 announced 2021-06-07; 1.0.0 general availability released 2021-07-12.  
- Notable stable releases include OpenSearch 1.1.0 (2021-10-05), 1.2.0 (2021-11-23), and 2.2.0 (2022-08-11).  
- The project has a Debian source package named "opensearch" (reference noted 2024-01-17).

## FAQs
### Q: What is OpenSearch?
A: OpenSearch is a free and open-source, distributed search engine and analytics platform that was created as a fork of Elasticsearch. It is written in Java and uses Apache Lucene for full-text search.

### Q: Is OpenSearch open-source and what license does it use?
A: Yes. OpenSearch is distributed under the Apache Software License 2.0.

### Q: Where is the OpenSearch source code hosted?
A: The OpenSearch source code is hosted on GitHub at https://github.com/opensearch-project/OpenSearch under the opensearch-project organization.

### Q: Which technology does OpenSearch use for full-text search?
A: OpenSearch uses the Apache Lucene search library for full-text queries.

## Why It Matters
OpenSearch provides an open-source, Apache 2.0–licensed alternative built from the Elasticsearch codebase. As a distributed, document-oriented search and analytics system written in Java, it leverages the well-known Apache Lucene library to deliver full-text search capabilities. The project established a rapid release cadence after its April 2021 start, delivering beta, release candidate, and general availability milestones within months and continuing with regular stable releases (for example, 1.1.0 and 1.2.0 in late 2021 and 2.2.0 in August 2022). Because it is packaged as free and open-source software and maintained in a public repository, OpenSearch enables organizations and developers to run, modify, and distribute a searchable, scalable data platform under permissive licensing. The combination of Lucene-based search, Java implementation, distributed design, and Apache 2.0 licensing positions OpenSearch as a practical choice for applications that need real-time search, analytics, or distributed document storage while keeping source access and permissive reuse terms.

## Notable For
- Being a fork of Elasticsearch started in April 2021 and publicly released with a beta on 2021-05-13.  
- Distributed, document-oriented design implemented in Java and using Apache Lucene for full-text queries.  
- Released under the Apache Software License 2.0, providing a permissive open-source license for the codebase.  
- Public development and distribution through the opensearch-project GitHub organization (https://github.com/opensearch-project/OpenSearch).  
- Rapid early release milestones: 1.0.0 Beta 1 (2021-05-13), 1.0.0 RC1 (2021-06-07), 1.0.0 GA (2021-07-12).

## Body
### Overview
- OpenSearch is a search engine and analytics platform.  
- It is a fork of Elasticsearch.  
- It is implemented in Java.  
- It uses the Apache Lucene search library for full-text queries.  
- It is licensed under the Apache Software License 2.0.

### Classification and Capabilities
- Instance types listed for OpenSearch include:  
  - document-oriented database management system  
  - distributed database management system  
  - search engine  
  - free and open-source software  
  - software

### History & Timeline
- Project start: April 2021 (start_time recorded as 2021-04-00).  
- 1.0.0 Beta 1: 2021-05-13 (announced as OpenSearch Beta 1).  
- 1.0.0 Release Candidate 1 (RC1): 2021-06-07.  
- 1.0.0 General Availability (stable): 2021-07-12.  
- 1.1.0 (stable): 2021-10-05.  
- 1.2.0 (stable): 2021-11-23.  
- 2.2.0 (stable): 2022-08-11.  
- Patch releases include 1.2.1 (2021-12-14), 1.2.2 (2021-12-16), 1.2.3 (2022-01-13), and 1.2.4 (2022-01-18).

### Architecture & Technology
- Programming language: Java.  
- Search library: Apache Lucene (used for full-text queries).  
- Distributed and document-oriented design enables scalable search and indexing.

### Licensing & Source
- License: Apache Software License 2.0.  
- Source code repository: https://github.com/opensearch-project/OpenSearch (GitHub organization: opensearch-project).  
- Debian package name: opensearch (Debian source package record noted).

### Resources & Identifiers
- Official documentation (English): https://opensearch.org/docs/latest/opensearch/index/  
- Project website and blog contain release announcements for versions listed.  
- Logo file: https://commons.wikimedia.org/wiki/Special:FilePath/Opensearch_Logo.svg  
- Wikidata / metadata: Wikipedia title "OpenSearch (software)"; sitelink_count: 6; wikipedia languages include bn, cs, de, en, pt, zh.

### Related Software
- Based on: Elasticsearch.  
- Uses: Apache Lucene (for full-text search functionality).

## References

1. [OpenSearch Beta 1. 2021](https://opensearch.org/blog/update/2021/05/opensearch-beta-announcement/)
2. [OpenSearch Release Candidate (RC1) is now available. 2021](https://opensearch.org/blog/update/2021/06/opensearch-release-candidate-announcement/)
3. [1.0 is released!. 2021](https://opensearch.org/blog/updates/2021/07/opensearch-general-availability-announcement/)
4. [OpenSearch 1.1.0 is here!. 2021](https://opensearch.org/blog/releases/2021/10/Launch-Announcement-1-1/)
5. [OpenSearch 1.2.0 is out now!. 2021](https://opensearch.org/blog/releases/2021/11/launch-announcement-1-2-0/)
6. [1.2.0. 2021](https://github.com/opensearch-project/OpenSearch/releases/tag/1.2.0)
7. [OpenSearch 2.2 is now available!. 2022](https://opensearch.org/blog/releases/2022/08/opensearch-2-2-is-now-available/)
8. [2.2.0. 2022](https://github.com/opensearch-project/OpenSearch/releases/tag/2.2.0)
9. [Release 1.2.1. 2021](https://github.com/opensearch-project/OpenSearch/releases/tag/1.2.1)
10. [Release 1.2.2. 2021](https://github.com/opensearch-project/OpenSearch/releases/tag/1.2.2)
11. [Release 1.2.3. 2022](https://github.com/opensearch-project/OpenSearch/releases/tag/1.2.3)
12. [Release 1.2.4. 2022](https://github.com/opensearch-project/OpenSearch/releases/tag/1.2.4)
13. [Release 1.3.0. 2022](https://github.com/opensearch-project/OpenSearch/releases/tag/1.3.0)
14. [Release 1.3.1. 2022](https://github.com/opensearch-project/OpenSearch/releases/tag/1.3.1)
15. [Release 1.3.4. 2022](https://github.com/opensearch-project/OpenSearch/releases/tag/1.3.4)
16. [Release 1.3.5. 2022](https://github.com/opensearch-project/OpenSearch/releases/tag/1.3.5)
17. [Release 1.3.6. 2022](https://github.com/opensearch-project/OpenSearch/releases/tag/1.3.6)
18. [Release 2.0.0. 2022](https://github.com/opensearch-project/OpenSearch/releases/tag/2.0.0)
19. [Release 2.0.1. 2022](https://github.com/opensearch-project/OpenSearch/releases/tag/2.0.1)
20. [Release 2.1.0. 2022](https://github.com/opensearch-project/OpenSearch/releases/tag/2.1.0)
21. [Release 2.2.1. 2022](https://github.com/opensearch-project/OpenSearch/releases/tag/2.2.1)
22. [Release 2.3.0. 2022](https://github.com/opensearch-project/OpenSearch/releases/tag/2.3.0)
23. [Release 2.4.0. 2022](https://github.com/opensearch-project/OpenSearch/releases/tag/2.4.0)
24. [Release 1.3.7. 2022](https://github.com/opensearch-project/OpenSearch/releases/tag/1.3.7)
25. [Release 2.4.1. 2022](https://github.com/opensearch-project/OpenSearch/releases/tag/2.4.1)
26. [Release 1.3.8. 2023](https://github.com/opensearch-project/OpenSearch/releases/tag/1.3.8)
27. [Release 2.5.0. 2023](https://github.com/opensearch-project/OpenSearch/releases/tag/2.5.0)
28. [Release 1.3.9. 2023](https://github.com/opensearch-project/OpenSearch/releases/tag/1.3.9)
29. [Release 2.6.0. 2023](https://github.com/opensearch-project/OpenSearch/releases/tag/2.6.0)
30. [Release 1.3.10. 2023](https://github.com/opensearch-project/OpenSearch/releases/tag/1.3.10)
31. [Release 2.7.0. 2023](https://github.com/opensearch-project/OpenSearch/releases/tag/2.7.0)
32. [Release 2.8.0. 2023](https://github.com/opensearch-project/OpenSearch/releases/tag/2.8.0)
33. [Release 2.9.0. 2023](https://github.com/opensearch-project/OpenSearch/releases/tag/2.9.0)
34. [Release 2.10.0. 2023](https://github.com/opensearch-project/OpenSearch/releases/tag/2.10.0)
35. [Release 1.3.13. 2023](https://github.com/opensearch-project/OpenSearch/releases/tag/1.3.13)
36. [Release 2.11.0. 2023](https://github.com/opensearch-project/OpenSearch/releases/tag/2.11.0)
37. [Release 2.11.1. 2023](https://github.com/opensearch-project/OpenSearch/releases/tag/2.11.1)
38. [Release 1.3.15. 2024](https://github.com/opensearch-project/OpenSearch/releases/tag/1.3.15)
39. [Release 2.12.0. 2024](https://github.com/opensearch-project/OpenSearch/releases/tag/2.12.0)
40. [Release 2.13.0. 2024](https://github.com/opensearch-project/OpenSearch/releases/tag/2.13.0)
41. [Release 1.3.16. 2024](https://github.com/opensearch-project/OpenSearch/releases/tag/1.3.16)
42. [Release 2.14.0. 2024](https://github.com/opensearch-project/OpenSearch/releases/tag/2.14.0)
43. [Release 1.3.17. 2024](https://github.com/opensearch-project/OpenSearch/releases/tag/1.3.17)
44. [Release 1.3.18. 2024](https://github.com/opensearch-project/OpenSearch/releases/tag/1.3.18)
45. [Release 2.15.0. 2024](https://github.com/opensearch-project/OpenSearch/releases/tag/2.15.0)
46. [Release 2.16.0. 2024](https://github.com/opensearch-project/OpenSearch/releases/tag/2.16.0)
47. [Release 2.17.0. 2024](https://github.com/opensearch-project/OpenSearch/releases/tag/2.17.0)
48. [Release 2.17.1. 2024](https://github.com/opensearch-project/OpenSearch/releases/tag/2.17.1)
49. [Release 2.18.0. 2024](https://github.com/opensearch-project/OpenSearch/releases/tag/2.18.0)
50. [Release 1.3.20. 2024](https://github.com/opensearch-project/OpenSearch/releases/tag/1.3.20)