JavaScript modules in workers

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

Baseline Status: Achieved Widely Available on Dec 6, 2025 (Cross-browser Newly Available since Jun 6, 2023).

Desktop Browser Engine Support

Google Chrome

80

Supported

Mozilla Firefox

114

Supported

Apple Safari

15

Supported

Microsoft Edge

80

Supported

Mobile Browser Engine Support

Chrome Android

80

Firefox Android

114

Safari iOS

15

Specifications and References

Specification ↗ Feature XML ↗

MDN Browser Compat Data Keys:

api.Worker.Worker.ecmascript_modules ↗ api.Worker.Worker.options_type_parameter ↗ javascript.operators.import.worker_support ↗ javascript.statements.import.worker_support ↗