Overview

When Google Tag Gateway (GTG) is enabled, Google tags are served from your first-party domain and can load before your CMP has set consent defaults. This creates a “late consent signal” — tags fire without a consent state, silently breaking Google Ads conversion tracking and GA4 measurement, and risking GDPR non-compliance.

This release updates Evidon UCP to fully support GTG. Consent defaults are declared before any tag can fire, In-CMP Signaling (ICS) handles late consent without relying on data layer order, and built-in diagnostics surface any timing issues directly in the browser console. Most customers receive this update automatically.

What is Google Tag Gateway?

Google Tag Gateway serves Google tags (gtm.js, gtag/js) from your own first-party domain instead of from googletagmanager.com. Available via one-click CDN setup on Cloudflare, Akamai, and Fastly, it improves tag delivery rates and reduces ad blocker impact — but it changes when tags load relative to your CMP.

As of the 2026 Google CMP Partner Program, certified CMPs are required to support GTG and declare all Consent Mode v2 signals before tags fire. Evidon UCP now meets these requirements out of the box.

What’s Changing in UCP

The following updates are included in this release. Most are automatic and require no action from publishers already using the Evidon template.

• Full Consent Mode v2 signal coverage. UCP now declares all six Consent Mode v2 signals — ad_storage, analytics_storage, ad_user_data, ad_personalization, functionality_storage, and security_storage — on every consent path including accept, decline, IAB save, CCPA opt-out, returning user, and no-consent-required regions.
• Consent default declared before tags fire. gtag('consent','default') is now declared before any tags fire, with EU/EEA region scoping, wait_for_update, and url_passthrough — satisfying Google’s 2026 CMP Partner Program “declare before fire” requirement.
• In-CMP Signaling (ICS) for GTG. On every consent update, UCP writes the In-CMP Signaling (ICS) object to window.google_tag_data.ics.entries for all six signals, allowing GTG to re-evaluate tags after a user decides without relying on data layer ordering alone.
• Late-consent detection & diagnostics. UCP logs a structured late-consent report to the browser console and exposes window.evidon.gtgDebug, flagging if Google tags can fire before consent and GTG is not deployed.
• New enableGoogleConsentSupport switch. Set window.evidon.enableGoogleConsentSupport = false to suppress all Google Consent Mode and GTG signals for properties that do not use Google tags. Default: enabled.
• New globalConsentDefaults config. Use window.evidon.globalConsentDefaults to pre-grant consent for DTC or no-banner regions and pages, taking precedence over flow-level defaults.
• TCF useractioncomplete event fix. A prior bug that prevented GTM/GTG from receiving a valid TCF consent event for IAB notices has been resolved.

Why This Matters

What You Need to Do

For most customers this update is applied automatically. Please review the following based on your setup:

• If you use the Evidon GTM template, confirm that Advanced Google Consent Mode is enabled in your tag configuration. This ensures the consent default state is set before Evidon scripts load and cookieless pings are sent while consent is pending.
• If you use the GTM Recipe implementation, all Google tags must be blocked via event triggers until the evidonConsentGiven data layer event fires. Review your trigger setup to confirm this is in place.
• If you have GTG deployed, no extra GTM configuration is needed — the new ICS object handles late consent automatically. Verify by checking window.evidon.gtgDebug in your browser console after a banner interaction.
• If a property does not use Google tags, set window.evidon.enableGoogleConsentSupport = false before the Evidon tag loads to suppress all consent signals.
• For DTC or no-banner regions, use window.evidon.globalConsentDefaults to pre-grant consent rather than relying on flow-level defaults.

Frequently Asked Questions

Will this update break my existing Evidon setup?

No. All changes are backwards-compatible. Publishers using the Evidon GTM template receive the new signal coverage and ICS support automatically with no configuration changes required.

What is a late consent signal and why does it matter?

A late consent signal occurs when a Google tag executes before the CMP has communicated the user's consent state. The tag may set cookies or collect data without consent, violating GDPR and other privacy regulations. With GTG, this risk is higher because first-party tags can load faster than expected.

Do I need to roll back GTG to fix a late consent signal?

No. Rolling back GTG forfeits its first-party measurement benefits. The recommended fix is Advanced Consent Mode combined with the new ICS object, which is now built into UCP automatically.

What is In-CMP Signaling (ICS)?

ICS is a Google-defined object (window.google_tag_data.ics.entries) that GTG reads to re-evaluate consent state after a user decides, without depending on the data layer alone. Evidon UCP now populates this object automatically on every consent update.

How do I verify GTG is working correctly with UCP?

Open your browser developer console, interact with the consent banner, and look for the [Evidon CMP] GTG Late Consent Report log. You can also inspect window.evidon.gtgDebug for raw detection data and window.google_tag_data.ics.entries to confirm all six signals are populated.

What is the difference between Basic and Advanced Consent Mode for GTG?

Basic Consent Mode blocks Google tags entirely until consent is granted. If the consent stub loads late under GTG, there is no measurement at all for that page load. Advanced Consent Mode lets tags load immediately and send cookieless pings while consent is denied, preserving conversion modeling. Advanced Consent Mode is strongly recommended for any site using GTG.

Questions & Support

For questions about this release or help reviewing your GTG setup, contact our support team or your dedicated Evidon Account Manager.