Shopify orders, credited everywhere you advertise.

No. Keep the native Meta and Google channels for catalog sync and basic pixel coverage. Signals adds server-side delivery to every platform you buy on, plus offline and POS revenue and customer-list audiences, and dedupes against whatever pixel is already installed so nothing double counts. The two run side by side, and Signals covers the platforms Shopify's native channels do not reach.

Yes. The Web Pixel API that Signals reads from runs on the extensible checkout the same way it runs on the classic one, so a checkout redesign or a move to Checkout Extensibility does not break delivery to any destination. Because the events come from the pixel API rather than theme code, an app or a UI change on the storefront leaves the server-side feed intact.

Headless storefronts use the JavaScript SDK or direct server-side event ingestion instead of the Shopify app, since there is no theme for a Web Pixel to attach to. The event mapping, hashing, and destinations are the same either way, so a Hydrogen or custom frontend reaches the same platforms as a themed store, and you choose whether events originate in the browser or your backend.

POS transactions fire the same webhook path as online orders, so a walk-in purchase or a buy-online-pickup-in-store sale is hashed, deduped against any matching online event, and delivered to the destinations you have mapped. A campaign gets credit for revenue that closed at the counter, matched by hashed identifier instead of a click, with no separate offline upload.

Where a destination supports refund reporting, yes. A refunded or partially refunded order is reconciled against the original conversion event, so the revenue a campaign is credited with reflects what the customer actually kept rather than what was briefly charged. Returns stop inflating measured performance, and the platforms optimize on net revenue instead of gross.