Relaxed-width SIMD (WebAssembly)Limited availability
Relaxed SIMD (Single Instruction Multiple Data) introduces local non-determinism, where the results of the instructions may vary based on hardware support.
Not yet supported in all major browsers — check the table and provide a fallback.
Browser support
DesktopChrome
1–113Not supported
114+Supportedsince May 30, 2023
Current: 155Edge
12–113Not supported
114+Supportedsince Jun 2, 2023
Current: 154Firefox
1–145Not supported
146+Supportedsince Dec 9, 2025
Current: 157Safari
✕Not supportedup to 27
Current: 27MobileChrome Android
18–113Not supported
114+Supportedsince May 30, 2023
Current: 155Firefox Android
4–145Not supported
146+Supportedsince Dec 9, 2025
Current: 157Safari iOS
✕Not supportedup to 27
Current: 27How to use
Not supported in Safari, Safari iOS. Use feature detection below and provide a fallback (or a polyfill) for those browsers.
Example
Full syntax and examples are on MDN — see the links below.
Feature detection
There’s no simple runtime check for this feature; rely on the support table and test in your target browsers.