api-docs/docs/node-tracker/markdown/node-tracker.adimpressionevent.costmodel.md
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[Home](./index.md) > [@snowplow/node-tracker](./node-tracker.md) > [AdImpressionEvent](./node-tracker.adimpressionevent.md) > [costModel](./node-tracker.adimpressionevent.costmodel.md)
## AdImpressionEvent.costModel property
The cost model for the campaign
<b>Signature:</b>
```typescript
costModel?: "cpa" | "cpc" | "cpm";
```