What is Server-to-Server (S2S) Tracking?

Server-to-server (S2S) tracking sends conversion and event data directly between servers (network → tracker, tracker → Meta CAPI, MMP → ad network) without relying on a browser pixel. More reliable under cookie blocking, ITP, and ad blockers.

Scenarios

• Affiliate postback — network → tracker on lead/sale.
• Outbound S2S — tracker → Facebook/Google for optimization.
• Conversion API — server events to Meta/TikTok alongside pixel.
• MMP — AppsFlyer/Adjust → network on install/event.

Benefits

Fewer losses vs client pixel; hashed PII can improve match rate. Signed requests and IP whitelists reduce fraud.

Limits

Needs dev/integration; pixel + S2S deduplication is mandatory. SKAdNetwork on iOS is a separate model, not classic S2S click id. Postback latency affects real-time bid optimization.

See also: postback, pixel tracking, conversion API, deduplication.