Tracking & DataEvent ID
What is an Event ID? The Deduplication Key and Why It Is Required
Also known as: event_id, event identifier, dedup key
Short answer
An Event ID is a unique marker for one conversion event. When the same event is sent from both the browser and the server, an identical marker tells the ad platform they are one event, not two.
Example
One purchase is sent from the browser with `event_id: ord-10482` and from the server with `event_id: ord-10482`. The ad platform merges them into one conversion.
Why this is a real problem, not a technical detail
| What happened | ROAS you see | Real ROAS | Decision taken |
|---|---|---|---|
| Markers match | 3.0 | 3.0 | Correct |
| No marker used | 6.0 | 3.0 | Budget raised on a losing campaign |
Rules for using it
- One event, one marker, used on every sending path.
- The event name must match on both paths.
- The marker must not change when an event is resent after a network failure.
- Never use a timestamp or a random number generated separately on each path.
Frequently asked questions
- What happens if no Event ID is used?
- One sale is counted twice. Your ROAS looks twice as good as reality, cost per conversion looks halved, and the auction learns from the wrong count. Every budget decision after that is wrong.
- What value works as an Event ID?
- A value guaranteed identical on both paths and never repeated, such as an order number or a lead identifier. Never use a timestamp, because browser and server clocks differ.
- Must the event name match too?
- Yes. Merging only happens when the event name and the Event ID both match. Events with different names count as two events even with the same marker.
Related terms
Konektor guides
Your ad numbers are only as accurate as the data behind them
Konektor captures the Click ID and sends conversions that close on WhatsApp, over the phone, or in a shop back to the ad platform.