Wasmtime WebAssembly Runtime

Wasmtime is a free and open-source, standalone runtime for WebAssembly (Wasm), developed by the Bytecode Alliance (a non-profit founded in 2019 by Mozilla, Fastly, Intel, and Red Hat). Written in Rust, Wasmtime focuses on security, correctness, and performance for running Wasm in server, edge, and embedded environments. Key features: WASI: full support for WASI (WebAssembly System Interface), providing POSIX-like capabilities (file I/O, environment variables, clocks, networking via wasi-http) with a capability-based security model where modules access only explicitly granted resources. Cranelift: uses the Cranelift code generator (also developed by Bytecode Alliance) for compiling Wasm to native machine code, providing fast compilation with good runtime performance. Security: Rust implementation provides memory safety. Runtime enforces Wasm's sandbox with deterministic execution, no arbitrary memory access, and configurable limits (fuel for metering, memory limits). Embedding: provides C, Rust, Go, Python, .NET, and Ruby APIs for embedding in host applications with fine-grained control over imported/exported functions. Component model: supports the WebAssembly Component Model for language-agnostic interop between modules written in different languages. WASI Preview 2 support. Debugging: core dump generation for post-mortem analysis. CLI: wasmtime command runs Wasm files directly. Cross-platform: Linux, macOS, Windows (x86_64, aarch64, s390x). Rust. Apache-2.0.