# zlib-ng

> compression library aiming to be a compatible drop-in replacement for zlib

**Wikidata**: [Q123183758](https://www.wikidata.org/wiki/Q123183758)  
**Source**: https://4ort.xyz/entity/zlib-ng

## Summary
zlib-ng is a cross-platform compression library and free software fork designed to serve as a compatible drop-in replacement for the standard zlib library. Distributed under the zlib License, it is actively maintained with stable versions released as recently as June 2023.

## Key Facts
- **License:** zlib License.
- **Category:** Software library, compression software, free software, fork.
- **Base Project:** Forked from **zlib**.
- **Platform:** Cross-platform.
- **Source Repository:** https://github.com/zlib-ng/zlib-ng
- **Latest Stable Version (Recorded):** 2.1.3 (released June 29, 2023).
- **Initial 2.x Stable Release:** Version 2.0.0 was released on March 16, 2021.
- **Package Availability:** Available via Arch Linux (`zlib-ng`), Gentoo (`sys-libs/zlib-ng`), Homebrew (`zlib-ng`), and AUR (`zlib-ng`).
- **Copyright Status:** Copyrighted.

## FAQs
### Q: Is zlib-ng a drop-in replacement for zlib?
A: Yes, zlib-ng is explicitly described as a compatible drop-in replacement for zlib, meaning it can be used in place of the original library without requiring changes to the dependent software.

### Q: Is zlib-ng free to use?
A: Yes, zlib-ng is free software distributed under the zlib License. This allows users to freely run, study, change, and distribute it and modified versions.

### Q: What platforms does zlib-ng support?
A: zlib-ng is cross-platform software, meaning it is capable of being implemented and operating on multiple computing platforms.

## Why It Matters
zlib-ng plays a critical role in the modern software infrastructure as a modernized alternative to the ubiquitous zlib compression library. By functioning as a "drop-in" replacement, it allows operating systems and applications to adopt updated compression capabilities without breaking compatibility with the vast ecosystem of software relying on the original zlib API.

The project is significant for its active development cycle, evidenced by frequent stable releases throughout 2021 and 2023. As a fork of zlib, it represents an evolutionary step for the compression standard, maintained as free software under the permissive zlib License. Its wide availability in major package managers—such as Gentoo, Arch Linux, and Homebrew—underscores its relevance to developers and system administrators seeking reliable, cross-platform compression solutions.

## Notable For
- **Compatibility:** Specifically engineered to be a compatible replacement for the standard zlib library.
- **Active Maintenance:** Demonstrates a rapid release cadence, with seven stable updates released in 2021 alone.
- **Cross-Platform Design:** Built to operate on multiple computing platforms.
- **Free Software Model:** Distributed with permissions to freely study, change, and distribute modified versions.
- **Broad Distribution:** Integrated into major software repositories including Arch Linux, Gentoo, and Homebrew.

## Body

### Overview and Classification
zlib-ng is a software library developed for data compression. It is classified as a "fork" of the original **zlib** library. The project aims to provide a modern implementation that maintains compatibility with the original while existing as a distinct entity. It is categorized technically as compression software and a software library.

### Licensing and Rights
The library is distributed under the **zlib License**. It is designated as **free software**, defined by the rights granted to users to freely run, study, change, and distribute the software and its modified versions. Despite being free software, the project retains a copyrighted status.

### Version History
The development of zlib-ng is documented through a series of stable releases, particularly within the 2.0 and 2.1 branches:

*   **2.0.x Series (2021):**
    *   **2.0.0:** Released March 16, 2021.
    *   **2.0.1:** Released March 17, 2021.
    *   **2.0.2:** Released March 23, 2021.
    *   **2.0.3:** Released May 13, 2021.
    *   **2.0.4:** Released June 11, 2021.
    *   **2.0.5:** Released June 25, 2021.
    *   **2.0.6:** Released December 24, 2021.
*   **2.0.x / 2.1.x Series (2023):**
    *   **2.0.7:** Released March 17, 2023.
    *   **2.1.2:** Released June 7, 2023.
    *   **2.1.3:** Released June 29, 2023.

### Distribution and Availability
zlib-ng is accessible across various software repositories and package managers, highlighting its cross-platform nature:
*   **Arch Linux:** Available as `zlib-ng`.
*   **AUR (Arch User Repository):** Available as `zlib-ng`.
*   **Gentoo:** Available as `sys-libs/zlib-ng`.
*   **Homebrew:** Formula name `zlib-ng`.
*   **Repology:** Project name `zlib-ng`.

The source code is publicly hosted and maintained at the GitHub repository `https://github.com/zlib-ng/zlib-ng`.

## References

1. [Source](https://github.com/zlib-ng/zlib-ng/blob/develop/LICENSE.md)
2. [Release 2.0.0. 2021](https://github.com/zlib-ng/zlib-ng/releases/tag/2.0.0)
3. [Release 2.0.1. 2021](https://github.com/zlib-ng/zlib-ng/releases/tag/2.0.1)
4. [Release 2.0.2. 2021](https://github.com/zlib-ng/zlib-ng/releases/tag/2.0.2)
5. [Release 2.0.3. 2021](https://github.com/zlib-ng/zlib-ng/releases/tag/2.0.3)
6. [Release 2.0.4. 2021](https://github.com/zlib-ng/zlib-ng/releases/tag/2.0.4)
7. [Release 2.0.5. 2021](https://github.com/zlib-ng/zlib-ng/releases/tag/2.0.5)
8. [Release 2.0.6. 2021](https://github.com/zlib-ng/zlib-ng/releases/tag/2.0.6)
9. [Release 2.0.7. 2023](https://github.com/zlib-ng/zlib-ng/releases/tag/2.0.7)
10. [Release 2.1.2. 2023](https://github.com/zlib-ng/zlib-ng/releases/tag/2.1.2)
11. [Release 2.1.3. 2023](https://github.com/zlib-ng/zlib-ng/releases/tag/2.1.3)
12. [Release 2.1.4. 2023](https://github.com/zlib-ng/zlib-ng/releases/tag/2.1.4)
13. [Release 2.1.5. 2023](https://github.com/zlib-ng/zlib-ng/releases/tag/2.1.5)
14. [Release 2.1.6. 2024](https://github.com/zlib-ng/zlib-ng/releases/tag/2.1.6)
15. [2.1.7. 2024](https://github.com/zlib-ng/zlib-ng/releases/tag/2.1.7)
16. [Release 2.2.1. 2024](https://github.com/zlib-ng/zlib-ng/releases/tag/2.2.1)
17. [Release 2.1.8. 2024](https://github.com/zlib-ng/zlib-ng/releases/tag/2.1.8)
18. [Release 2.2.2. 2024](https://github.com/zlib-ng/zlib-ng/releases/tag/2.2.2)
19. [2.2.3. 2025](https://github.com/zlib-ng/zlib-ng/releases/tag/2.2.3)
20. [Release 2.2.4. 2025](https://github.com/zlib-ng/zlib-ng/releases/tag/2.2.4)
21. [Release 2.2.5. 2025](https://github.com/zlib-ng/zlib-ng/releases/tag/2.2.5)
22. [2.3.1. 2025](https://github.com/zlib-ng/zlib-ng/releases/tag/2.3.1)
23. [Release 2.3.2. 2025](https://github.com/zlib-ng/zlib-ng/releases/tag/2.3.2)
24. [Release 2.3.3. 2026](https://github.com/zlib-ng/zlib-ng/releases/tag/2.3.3)