Extism

Extism is a universal plug-in system designed to make all software programmable. It features an embeddable, safe, and performant runtime that can be integrated into over 13 programming languages via official SDKs. Extism utilizes WebAssembly (Wasm) to execute plug-in code securely within the same OS process as the host program, leveraging Wasm's sandbox isolation architecture for safety and performance.

The core of Extism is built in Rust, chosen for its reliability and performance. The system exposes runtime APIs through Foreign Function Interface (FFI), making it accessible from multiple language environments. Extism's plug-ins can be written in five languages using official Plug-in Development Kits (PDKs), with plans to expand language support.

Extism defines a set of functions linked from the host runtime to the Wasm module, allowing plug-ins to make network calls, persist variables, read host configuration data, and handle complex data exchange. The system also supports the WebAssembly System Interface (WASI) for a rich POSIX-like system interface, though direct disk access is restricted for security reasons.

The platform is fully open-source under the BSD-3 license, with all components available on GitHub. Users are encouraged to explore the SDK and PDK documentation for examples and to contribute via GitHub or join the community on Discord for support and feedback.