Implementing Apple's LZRAVEN Codec in C Using Claude

A developer has introduced liblzraven — an open-source implementation of Apple's new compression codec, written entirely with the help of the Claude AI.

Compiled by Sergey KostenchukPublished 2026-07-30Updated 2026-08-22

2026-07-30 Coding Anthropic

💻 Implementing Apple's LZRAVEN Codec in C Using Claude

A developer has introduced liblzraven — an open-source implementation of the LZRAVEN (COMPRESSION_LZRAVEN) codec used in Apple OS 27 updates. The library was written entirely using the Claude AI and has been verified for compatibility with the original. On Apple Silicon (M4 Pro), decoding speeds reach ~954 MB/s, which is 3 times faster than xz (-6).

🌍 The emergence of an open-source implementation for a proprietary Apple codec is critical for third-party system developers who need to unpack Apple updates without using closed macOS libraries.

👤 This is an excellent example of how AI assists in reverse engineering and implementing complex system components, ensuring reliability through automated testing.

Source 1: https://github.com/anat0m1a/liblzraven

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