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WASI preview 3 was stabilized in late 2025 and adds what preview 2 lacked: native async, bidirectional streams, and inter-component concurrency with specified semantics. Portability and async are no longer a trade-off, since one async component runs unchanged on wasmtime, WasmEdge, JCO and the main commercial runtimes. API gateways and SaaS extension plugins are the strongest production cases.
Free threading in Python became real with 3.13 and PEP 703, which makes the GIL optional at build time: the standard binary keeps it, while the separate python3.13t binary removes it. Thread-heavy orchestration code gains most; NumPy-style work that already released the GIL barely changes. Single-thread performance on that build drops around 40 percent.
WASI 0.3, also known as preview 3, was ratified on June 11, 2026, adding native asynchronous concurrency to the WebAssembly component model through streams, futures, and async functions. It fixes old fragmentation across languages and runtimes, enables real composition between Wasm services, and paves the way for cooperative threads planned in upcoming 0.3.x releases.
