JavaScript modules in service workers

The navigator.serviceWorker.register() method accepts { type: "module" } to load scripts that use import and export. Also known as ECMAScript modules or ESM in service workers.

Baseline Status: Achieved Newly Available on Jan 13, 2026 across core engines.

Desktop Browser Engine Support

Google Chrome

91

Supported

Mozilla Firefox

147

Supported

Apple Safari

15

Supported

Microsoft Edge

91

Supported

Mobile Browser Engine Support

Chrome Android

91

Firefox Android

147

Safari iOS

15

Specifications and References

Specification ↗ Feature XML ↗

MDN Browser Compat Data Keys:

api.ServiceWorker.ecmascript_modules ↗ javascript.statements.import.service_worker_support ↗