# ksqlDB

> database built on Apache Kafka

**Wikidata**: [Q107291842](https://www.wikidata.org/wiki/Q107291842)  
**Source**: https://4ort.xyz/entity/ksqldb

## Summary
ksqlDB is a database management system built directly on Apache Kafka. Developed by Confluent Inc., it is classified as free software that allows users to run, study, change, and distribute the code. The project is accessible via its official website and a public GitHub repository.

## Key Facts
- **Developer:** Confluent Inc.
- **Core Technology:** Uses Apache Kafka as its foundation.
- **Classification:** Defined as a "database management system" and "free software."
- **Official Website:** https://ksqldb.io/
- **Source Code Repository:** Hosted on GitHub at `https://github.com/confluentinc/ksql`.
- **Latest Recorded Version (Preferred):** Version 5.0.0, released on July 31, 2018.
- **Version History:** Includes earlier releases such as version 0.3 (Jan 5, 2018) and version 0.4 (Feb 1, 2018).
- **Social Media:** Official Twitter account launched on October 18, 2019.

## FAQs
### Q: What exactly is ksqlDB?
A: ksqlDB is a database management system specifically built on top of Apache Kafka. It is designed to process data streams using a SQL-like interface.

### Q: Who develops and maintains ksqlDB?
A: ksqlDB is developed by Confluent Inc. The software is open-source, with its code available on GitHub.

### Q: Is ksqlDB free to use?
A: Yes, ksqlDB is classified as free software. This means users are free to run, study, change, and distribute it and any modified versions.

### Q: When was the "5.0.0" version of ksqlDB released?
A: The 5.0.0 version, listed as a preferred release, was published on July 31, 2018.

## Why It Matters
ksqlDB occupies a specific niche in the data infrastructure landscape by converging the capabilities of a database with the streaming power of Apache Kafka. While traditional databases often operate on static data states, ksqlDB is architected to handle high-throughput, real-time data streams directly within the Kafka ecosystem. This allows developers to build applications that react immediately to events as they occur, rather than waiting for batch processing.

Its significance is further underscored by its classification as free software, lowering the barrier to entry for organizations adopting streaming architectures. By providing a standard database interface for stream processing, it abstracts the complexity of native Kafka programming, making real-time data more accessible to a wider range of developers.

## Notable For
- **Architecture:** It is one of the few database systems explicitly built *on* Apache Kafka rather than merely connecting to it.
- **Open Source Status:** Unlike proprietary streaming solutions, it is fully classified as free software with a public codebase.
- **Rapid Early Development:** The project released multiple significant versions (0.3, 0.4, and 5.0.0) within the first seven months of 2018.
- **Convergence:** It combines the roles of a database management system and a stream processing tool.

## Body

### Technical Definition and Usage
ksqlDB is a specialized database management system. Its primary architectural distinction is its foundation upon Apache Kafka. While standard databases typically rely on disk storage for tables, ksqlDB leverages Kafka's log-structured storage to manage data. It is categorized as free software, meaning it is distributed under terms that permit users to freely run, study, modify, and redistribute the software.

### Development and Version History
The project is managed by Confluent Inc., a company founded by the creators of Apache Kafka. The development timeline recorded in public repositories shows active maintenance starting in early 2018.

*   **Version 0.3:** Released on January 5, 2018.
*   **Version 0.4:** Released on February 1, 2018.
*   **Version 5.0.0:** Released on July 31, 2018. This version is marked as the "preferred" release in the data history, indicating a significant milestone or stable build in the project's timeline.

### Online Presence and Resources
Confluent Inc. maintains a suite of online resources for the software. The official website is `ksqldb.io`. The source code is publicly hosted on GitHub at `https://github.com/confluentinc/ksql`. The project established a formal social media presence on October 18, 2019, with the launch of its official `@ksqlDB` Twitter account. The software is copyrighted but distributed as free software.

## References

1. [Release 0.3. 2018](https://github.com/confluentinc/ksql/releases/tag/v0.3)
2. [Release 0.4. 2018](https://github.com/confluentinc/ksql/releases/tag/v0.4)
3. [Release 5.0.0. 2018](https://github.com/confluentinc/ksql/releases/tag/v5.0.0)