React Error: “SharedArrayBuffer is not defined” in Firefox
You need to set two response headers for your document: Cross-Origin-Opener-Policy: same-origin Cross-Origin-Embedder-Policy: require-corp These are new security requirements for using SharedArrayBuffer. You can check in code if cross origin isolation is enabled: if (crossOriginIsolated) { // SharedArrayBuffer is available } https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/SharedArrayBuffer