${MACRO}
Xandr (Microsoft Invest) Macros
Xandr uses the same dollar-brace style as DV360, with a small, stable set of macros. Its documentation is unusually direct about the difference between a cachebuster and an auction ID, which matters more than it sounds for reconciliation.
Click tracking
| Macro | Expands to |
|---|---|
| ${CLICK_URL} | The click-tracking URL. |
| ${CLICK_URL_ENC} | The click-tracking URL, encoded.Needed by some third-party ad servers when the tracker is nested. |
Uniqueness
| Macro | Expands to |
|---|---|
| ${CACHEBUSTER} | A random string, generated once per bid response.Shared across placements in the same bid request — not unique per impression. |
| ${AUCTION_ID} | A unique 64-bit ID for the specific auction.The right choice for reconciliation and discrepancy tracking. |
The one that catches people out
Use ${AUCTION_ID} rather than ${CACHEBUSTER} when the value has to be unique per impression. The cachebuster is generated once per bid response, so if one bid request contains several placements they all receive the same value — which quietly breaks any discrepancy analysis that assumes uniqueness. The auction ID is unique per placement and matches the corresponding bid response.
To check how many times a value has been encoded before trafficking it, the URL encoder and decoder reports encoding depth — which is usually faster than testing an impression to find out.
Verified against Microsoft Learn — Click tracking and cache-busting examples on 30 July 2026. Platforms change macros without notice — check the source before relying on this for a live campaign.