CMP Selection for GA4: Cookiebot vs OneTrust vs Usercentrics vs Complianz (2026)

Which CMP should I use with GA4 in 2026?

For Consent Mode V2 with GA4, the four most widely deployed CMPs are Cookiebot (strong GTM template, broad EU compliance), OneTrust (enterprise feature depth, complex for smaller sites), Usercentrics (clean UX, strong A/B testing for accept rates), and Complianz (WordPress-native, budget-friendly). The practical choice for 80% of businesses: Cookiebot for mid-market EU/UK sites, OneTrust for enterprise with complex multi-jurisdiction requirements. The single most important CMP criterion for GA4 specifically: a verified GTM template in the Community Template Gallery that correctly implements Consent Mode V2's four parameters (including ad_user_data and ad_personalization). CMPs without a reliable GTM template require custom JavaScript integration that introduces implementation risk.

The four CMPs compared

Cookiebot (Usercentrics group)

Pricing: Free for single domain under 100 pages, then from €9/month (single domain) to €23+/month (multi-domain). Agency/enterprise plans available.

GTM integration: Official GTM Community Template Gallery template. Handles default consent state and update state automatically with minimal configuration. The template accepts your Cookiebot ID and maps consent categories to GA4/Google Ads consent types.

Consent Mode V2 support: Full — all four parameters (analytics_storage, ad_storage, ad_user_data, ad_personalization) handled by the template.

Strengths:

• Simplest reliable GTM integration of the four
• Automatic cookie scanning and categorisation (re-scans monthly)
• Good multi-language support (40+ languages)
• GDPR, UK GDPR, CCPA, LGPD compliant
• Solid documentation and established track record

Weaknesses:

• Limited banner A/B testing on lower-tier plans
• Less granular control over banner design vs Usercentrics
• Cookie scan accuracy not perfect (sometimes misclassifies or misses new cookies)

Best for: SMB to mid-market businesses needing reliable, low-maintenance GDPR compliance with minimal GTM complexity. The default choice for UK and EU sites that don't have complex multi-jurisdiction requirements.

OneTrust

Pricing: Starts around £1,000–£5,000/year for the Consent Management module depending on traffic volume. Enterprise pricing is bespoke.

GTM integration: Official GTM template available. More complex to configure than Cookiebot — requires mapping OneTrust consent categories to GA4 consent types manually. Higher implementation overhead.

Consent Mode V2 support: Full, but requires correct category mapping configuration. OneTrust's generic consent groups ("Targeting Cookies," "Performance Cookies") must be explicitly mapped to ad_storage, ad_user_data, etc. Misconfiguration is common.

Strengths:

• Industry-leading compliance depth (GDPR, CCPA, CPRA, LGPD, PDPA, and many more)
• Universal Consent and Preference Management (UCPM) for cookie + non-cookie consent
• Advanced banner design and A/B testing
• Enterprise governance features (audit trails, consent records for DSARs)
• Integrates with OneTrust's broader privacy management platform

Weaknesses:

• Significantly more expensive than alternatives
• High implementation complexity — often requires OneTrust specialist
• GTM template more complex to configure correctly for Consent Mode V2
• Over-engineered for small-to-mid businesses

Best for: Enterprise businesses with complex multi-jurisdiction compliance requirements, legal teams that need audit trails for DSARs, or organisations already using OneTrust's broader privacy platform.

Usercentrics

Pricing: From €60/month (Starter) to enterprise pricing. Starter plan includes 1 domain, basic features.

GTM integration: Official GTM template. Slightly more involved than Cookiebot but well-documented. Consent Mode V2 supported via the template.

Consent Mode V2 support: Full, with service-level mapping interface in the Usercentrics dashboard — you map Usercentrics consent services to GA4 consent types in a UI rather than in GTM configuration. Cleaner workflow than OneTrust.

Strengths:

• Superior banner design/UX customisation
• Best-in-class A/B testing for consent rate optimisation (direct impact on GA4 data quality — higher accept rates = less modelled data)
• Real-time analytics on consent rates by banner variant, device, country
• Very clean admin interface
• Strong EU/DACH market presence

Weaknesses:

• More expensive than Cookiebot at comparable features
• Smaller community/template ecosystem than Cookiebot or OneTrust

Best for: Businesses where consent accept rate is a meaningful business metric and where banner UX investment is justified. The A/B testing capability can directly improve GA4 data quality by increasing consent rates — worth the price premium if you're losing significant data to consent rejection.

Complianz

Pricing: Free WordPress plugin (basic), €49/year (Pro single site), €149/year (unlimited sites). Significantly cheaper than the other three.

GTM integration: GTM plugin for WordPress that handles Consent Mode V2 integration. Works with the Complianz WordPress plugin.

Consent Mode V2 support: Full via the plugin + GTM combination.

Strengths:

• Extremely cost-effective
• Deep WordPress integration (WooCommerce, Elementor, etc.)
• No cookie scanning limits
• Good multi-language support
• GDPR + UK GDPR + CCPA covered

Weaknesses:

• WordPress-only (not suitable for non-WordPress sites)
• No A/B testing for consent rates
• Less enterprise-grade than the other options
• Support quality variable compared to paid SaaS CMPs

Best for: WordPress/WooCommerce sites with budget constraints and straightforward compliance needs. The clear choice for WordPress properties where Cookiebot's pricing is a barrier.

The accept rate factor for GA4 data quality

CMP choice directly affects your GA4 data quality through accept rates. A banner that 60% of users accept gives you 60% of your data from fully consented measurement + modelled data for the remaining 40%. A banner that 30% accept gives you much less signal.

Accept rate benchmarks by market (2026):

• UK: 45–65% depending on banner design
• Germany: 25–40%
• France: 35–55%
• Netherlands: 40–60%
• US (CCPA notice only): 75–90%

Factors that improve accept rates:

• "Accept all" button prominently above "Reject" or "Manage"
• Colour contrast — accept button uses primary brand colour
• Simple language (avoid legal jargon in the banner headline)
• Fewer consent category options (fewer choices = higher acceptance)
• Mobile-optimised banner design

Factors that reduce accept rates:

• Equal visual weight to accept and reject buttons (dark pattern prohibitions under TCF 2.2)
• Buried accept button
• Long lists of third parties on first view
• Slow CMP load time (users reject or close before the banner fully renders)

Usercentrics' A/B testing for banner design is the most direct lever for improving accept rates, which directly improves GA4 data completeness.