Sandbox Fusion is a multifunctional code sandbox specifically designed for large language models (LLMs). It supports up to 20 programming languages and can comprehensively test multiple domains, including programming, mathematics, and hardware programming. Sandbox Fusion integrates over 10 coding-related assessment datasets, which feature standardized data formats and are accessible via a unified HTTP API. Additionally, Sandbox Fusion is optimized for cloud infrastructure deployment and offers built-in security isolation when privileged containers are available. Developed by ByteDance, Sandbox Fusion aims to provide developers with a secure and efficient code testing environment.