What Are Tracking Pixels?
Understand what tracking pixels do, which ad platforms SMLLR supports, and how account defaults and per-QR overrides work together.
What Tracking Pixels Do
A tracking pixel is a small snippet of JavaScript that reports a page view (or other event) back to an advertising platform. SMLLR can inject these snippets into the redirect page a scanner briefly lands on, so every QR scan is reported to your ad accounts just like a website visit would be.
This is what makes it possible to retarget people who scanned your QR code — show them ads later, build Lookalike/similar audiences from your scanner base, and measure QR performance inside the same ad platforms you already use for digital campaigns.
Supported Platforms
Google Ads and GA4 share a single loader script (gtag.js) — if you set both, SMLLR loads it once and configures both, so nothing double-fires.
| Platform | ID You'll Need | Where To Find It |
|---|---|---|
Meta (Facebook/Instagram) Pixel | Numeric Pixel ID | Meta Events Manager |
Google Ads | Conversion ID (format | Google Ads → Tools → Conversions |
Google Analytics 4 (GA4) | Measurement ID (format | GA4 → Admin → Data Streams |
LinkedIn Insight Tag | Numeric Partner ID | LinkedIn Campaign Manager → Account Assets → Insight Tag |
What Actually Fires on a Scan
Today, SMLLR fires each platform's automatic page-view event on every scan of a QR code that has tracking pixels configured:
Lead/conversion events tied to a form submission (e.g. Meta's Lead event or Google's generate_lead) are not available yet — this is on the roadmap and will be documented here once it ships.
| Platform | Event Fired |
|---|---|
Meta Pixel |
|
Google Ads / GA4 |
|
LinkedIn Insight Tag | Automatic page-view event, set by the Insight Tag script itself |
Account Defaults vs. Per-QR Overrides
Tracking pixel IDs work at two levels, and SMLLR merges them automatically:
You don't have to override every field on a QR code. Fill in only the platforms you want to differ from the account default — everything else keeps inheriting automatically, including if you change the account default later.
| Level | Where It's Set | Behaviour |
|---|---|---|
Account default | Settings → Tracking Pixels | Applies to every QR code in your account that doesn't set its own value |
Per-QR override | QR editor → Tracking Pixels section | Applies only to that one QR code, replacing the account default for whichever fields you fill in |
Which Plans Include Tracking Pixels?
Tracking pixels — both account-level defaults and per-QR overrides — are available on the Premium plan and above. During your 14-day free trial, you have full access at no charge.
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