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Consent & Privacy

Tracking without consent is no longer just an ethical grey area — it is a legal liability. GDPR, the ePrivacy Directive, and Google’s own enforcement actions have made consent management a core technical competency for anyone running analytics or advertising tags.

This section covers everything you need to implement consent correctly: what Consent Mode v2 actually does under the hood, how to connect your CMP to GTM, how to handle non-Google tags that don’t respect Consent Mode, and how to test that your setup does what you think it does.

Start here

Section titled “Start here”

If you are new to Consent Mode, read these two articles first. They give you the conceptual foundation you need before touching any GTM configuration.

Consent Mode v2 Explained What the seven consent types actually do, how cookieless pings work, and why behavioral modeling matters.
Basic vs. Advanced Consent Mode The single most consequential configuration decision in your consent setup — and how to choose correctly.

GTM configuration

Section titled “GTM configuration”
Consent Mode GTM Setup Step-by-step: setting default consent state, updating on user interaction, and configuring per-tag consent checks.
CMP Integration Connecting Cookiebot, OneTrust, Usercentrics, CookieYes, and other CMPs to Consent Mode via GTM.
Consent Initialization Timing The most common Consent Mode misconfiguration — and the trigger order that fixes it.
Consent State via DataLayer Managing and reading consent state in the dataLayer for non-native tags and custom logic.

Advanced topics

Section titled “Advanced topics”
Advanced Consent Mode Cookieless pings, behavioral modeling, and the privacy tradeoffs of sending data before consent.
Consent for Non-Google Tags How to gate Meta Pixel, TikTok, LinkedIn, and other tags that don't natively respect Consent Mode.
Cross-Domain Consent Consistent consent state across multiple domains — and what breaks when you get it wrong.
Server-Side Consent Consent handling in server-side GTM — the architecture, the event model, and PII redaction.

Testing

Section titled “Testing”
Testing Your Consent Implementation A complete testing protocol: cookies, network requests, GTM Preview mode, GA4 DebugView, and automated verification.

What you need to understand before starting

Section titled “What you need to understand before starting”

Consent Mode is a signal-passing system. You pass signals to Google’s tags describing the user’s consent choices. Google’s tags then modify their behavior accordingly — collecting less data, dropping cookies, or firing cookieless pings instead.

What Consent Mode does not do:

  • It does not show a consent banner to your users
  • It does not automatically block non-Google tags
  • It does not guarantee legal compliance on its own
  • It does not replace your CMP

The CMP (Consent Management Platform) is the tool that shows the banner, records the choice, and calls the consent update function. GTM + Consent Mode is the mechanism that receives that signal and acts on it. You need both.

The articles in this section assume you have (or are about to get) a CMP. If you don’t have one, start with CMP Integration to understand your options before configuring anything in GTM.