What is server-to-server (S2S) tracking?
Server-to-server tracking sends event data directly from one backend system to another. For example, an order service can send a paid order to an analytics pipeline, which then forwards a permitted purchase event to an ad platform. The delivery step does not depend on a page remaining open in the browser.
S2S describes the connection between servers. It does not explain how every event was first observed. A product click still needs code in the website or app to detect it before that event can enter a server pipeline.
Where is it useful?
- Reporting backend outcomes such as paid orders, refunds, or qualified leads.
- Sending events to several destinations through one controlled pipeline.
- Validating fields and applying consent or destination rules before delivery.
- Retrying a failed delivery without asking a visitor to repeat an action.
Use stable event or order IDs so a retry does not create a second conversion. Keep timestamps and source records for reconciliation. An S2S request can still fail, and the destination can still reject an event with missing fields.
For a setup that also collects browser and app actions, see server-side measurement. Browser and server copies of one action need event deduplication.
How Hardal handles it
Hardal provides an S2S endpoint that accepts events from your backend and forwards them to destinations such as GA4, Meta and Adjust. You can hash personal data and apply destination rules before anything leaves your servers.
Related terms: Server-side measurement, Event deduplication, Analytics event, First-party data