We are planning to deprecate the use by Firefox add-ons of the techniques described in this document.

Don't use these techniques to develop new add-ons. Use WebExtensions instead.

If you maintain an add-on which uses the techniques described here, consider migrating it to use WebExtensions instead.

Add-ons developed using these techniques might not work with multiprocess Firefox (e10s), which is already the default in Firefox Nightly and Firefox Developer Edition, and will soon be the default in Beta and Release versions of Firefox. We have documentation on making your add-ons multiprocess-compatible, but it will be more future-proof for you to migrate to WebExtensions.

A wiki page containing resources, migration paths, office hours, and more, is available to help developers transition to the new technologies.


Generate or parse UUIDs.


It exports a single function, uuid().

For more details about UUID representations and what they are used for by the platform see the MDN documentation for JSID.

Generate UUID

To generate a new UUID, call uuid() with no arguments:

let uuid = require('sdk/util/uuid').uuid();

Parsing UUID

To convert a string representation of a UUID to an nsID, pass the string representation to uuid():

let { uuid } = require('sdk/util/uuid');
let firefoxUUID = uuid('{ec8030f7-c20a-464f-9b0e-13a3a9e97384}');




Generate a new UUID, or convert a string representation of a UUID to an nsID.


stringId : string
String representation of a UUID, such as:


Optional. If this argument is supplied, it will be converted to an nsID and returned. Otherwise a new nsID will be generated and returned.



nsID : A UUID, represented as an nsID object.

Document Tags and Contributors

 Contributors to this page: wbamberg, jsantell
 Last updated by: wbamberg,