api-docs/docs/node-tracker/markdown/node-tracker.coreconfiguration.callback.md
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[Home](./index.md) > [@snowplow/node-tracker](./node-tracker.md) > [CoreConfiguration](./node-tracker.coreconfiguration.md) > [callback](./node-tracker.coreconfiguration.callback.md)
## CoreConfiguration.callback property
<b>Signature:</b>
```typescript
callback?: (PayloadData: PayloadBuilder) => void;
```