---
title: timestamp
framework: storekit
role: symbol
role_heading: Instance Property
path: storekit/skadimpression/timestamp
---

# timestamp

A number that represents the UNIX time, in milliseconds, of the ad impression.

## Declaration

```swift
var timestamp: NSNumber { get set }
```

## Mentioned in

Generating the signature to validate view-through ads

## Discussion

Discussion Ad networks generate the timestamp, represented as UNIX time in milliseconds, at the time you begin to serve the ad to users.

## See Also

### Creating a signature

- [init(sourceAppStoreItemIdentifier:advertisedAppStoreItemIdentifier:adNetworkIdentifier:adCampaignIdentifier:adImpressionIdentifier:timestamp:signature:version:)](storekit/skadimpression/init(sourceappstoreitemidentifier:advertisedappstoreitemidentifier:adnetworkidentifier:adcampaignidentifier:adimpressionidentifier:timestamp:signature:version:).md)
- [version](storekit/skadimpression/version.md)
- [adNetworkIdentifier](storekit/skadimpression/adnetworkidentifier.md)
- [sourceIdentifier](storekit/skadimpression/sourceidentifier.md)
- [adCampaignIdentifier](storekit/skadimpression/adcampaignidentifier.md)
- [advertisedAppStoreItemIdentifier](storekit/skadimpression/advertisedappstoreitemidentifier.md)
- [adImpressionIdentifier](storekit/skadimpression/adimpressionidentifier.md)
- [sourceAppStoreItemIdentifier](storekit/skadimpression/sourceappstoreitemidentifier.md)