Upgrade from v1 to v2

The Environment interface now exports getClientId which replaces the previous generateUUID method, simplifying the interactions required.

generateUUID has been deprecated, along with the entire Storage interface.

This breaking change will affect customers a custom Relay environment, which is a small subset of implementations.

Relay now uses fetch with keepalive instead of navigator.sendBeacon to transmit analytics events, since keepalive is now supported by all major browsers (including Firefox 133+).

The change ensures event payloads are visible in browser developer tools, and enhances security by making it possible to pass authentication tokens via request headers instead of the request URL. The keepalive option preserves the same delivery guarantees as sendBeacon, ensuring events are sent even when the page is being unloaded.

As part of the change, the emit method is now asynchronous and returns a Promise. Relay will also throw an error if an event doesn’t conform to the base Event Protocol payload structure.