Extensibility
Documentation Concepts Extensibility WebAssembly is a sandboxing technology which can be used to extend the Istio proxy (Envoy). The Proxy-Wasm sandbox API replaces Mixer as the primary extension mechanism in Istio. WebAssembly sandbox goals: Efficiency - An extension adds low latency, CPU, and memory overhead.
https://istio.io/latest/docs/concepts/wasm/