Universal Development with Wasi: Building Secure Cross-Platform Apps Using Webassembly System Interface

As software development increasingly demands portability, performance, and security across a wide range of platforms—from cloud servers to edge devices—WebAssembly (Wasm) has emerged as a compelling solution. In 2025, the maturation of the WebAssembly System Interface (WASI) marks a significant milestone in enabling universal application development that is both cross-platform and sandboxed by design. This paper investigates WASI’s modular system interface, its capability-based security model, and the practical implications of deploying applications across heterogeneous environments. Through architectural analysis, real-world use cases, and empirical benchmarks, we demonstrate that WASI offers a viable alternative to traditional containerization for many workloads. We further explore how WASI bridges the gap between performance, portability, and safety, paving the way for a new era of secure and efficient application development.