---
slug: makros-adserver
title: "What do the macros in the tracking code mean?"
category: messung
locale: en
updated: 2026-10-15
keywords: ["macro","IMPRESSION_ID","CACHEBUSTER","CONSENT","ad server","placeholder"]
questions: ["What is [IMPRESSION_ID] and what happens if the macro is not replaced?","Macro is not replaced","What is a cache buster?","Impression ID in the ad server","What does [CONSENT] mean?","What does [SITE_DOMAIN] mean?","Why does my copied code measure nothing?"]
url: https://bench.metrunio.com/en/help/makros-adserver
---

# What do the macros in the tracking code mean?

**What is [IMPRESSION_ID] and what happens if the macro is not replaced?**

Your ad server replaces [IMPRESSION_ID] with the identifier of the individual delivery and [CACHEBUSTER] with a random value. If [IMPRESSION_ID] is left unreplaced, the collector detects it and gives the pixel its own impression ID per delivery. The impression then counts, but the viewability tag reports nothing: without a shared identifier, viewability cannot be matched to a delivery.

| Macro | Replaced by | Purpose |
| --- | --- | --- |
| [IMPRESSION_ID] | identifier of the individual delivery | joins pixel, viewability and click |
| [CACHEBUSTER] | a random value per call | stops a proxy from swallowing the delivery |
| [CONSENT] | 1 when the publisher’s consent has been given, otherwise 0; set by the consent tool or the ad server | without 1 nothing is stored and no view identifier is set; a placeholder left in place counts as no consent |
| [SITE_DOMAIN] | domain of the website the ad runs on | shows in the report where the ad ran; if the placeholder stays, Metrunio reads the website from the referrer |

Macro syntax differs per ad server: some use %%CACHEBUSTER%%, others ${CACHEBUSTER}. Replace our placeholders with your system’s syntax before you traffic the creative.

If your ad server only ever delivers the creative with consent, choose “My ad server delivers this creative only with consent” in the tracking generator. The code then contains a fixed 1 instead of [CONSENT]. This is your statement; Metrunio does not check it, and it is recorded on every element generated this way. It does not replace proof of your visitors’ consent. Choose it only for a delivery chain you have checked and documented: which ad server, which publisher, which consent text, who is responsible. Beforehand, confirm with a negative test that without matching consent neither the measurement tag nor a positive signal is delivered. Metrunio does not check every single ad contact; you still need to resolve any sign of a misconfiguration.

> **Caution:** If pixel and viewability tag receive different impression IDs, viewable impressions appear without a matching delivery. That surfaces as a finding under “Data status”.

## Also asked

- Macro is not replaced
- What is a cache buster?
- Impression ID in the ad server
- What does [CONSENT] mean?
- What does [SITE_DOMAIN] mean?
- Why does my copied code measure nothing?

## Related

- https://bench.metrunio.com/en/help/impression-pixel
- https://bench.metrunio.com/en/help/viewability-tag
- https://bench.metrunio.com/en/help/post-view-messung
- https://bench.metrunio.com/en/help/keine-post-view-touchpoints
- https://bench.metrunio.com/en/help/publisher-website