Best Cookie Consent Management Platforms (CMPs), Compared

There are more consent management platforms than most people realise, and the honest answer to "which one should I use" is that the differences between the major players matter less than what happens after installation. Here's a rundown of the field, and why that second part is the one that actually causes problems.

The Major Players

• Cookiebot (now part of Usercentrics) — widely used, straightforward setup, solid free tier for smaller sites.
• OneTrust — the enterprise default, extensive configurability, correspondingly heavier to set up and maintain.
• Cookie-Script — lightweight, fast to deploy, popular with agencies managing several client sites for exactly that reason.
• CookieYes — WordPress-friendly, generous free tier, a common choice for smaller UK businesses.
• Osano — leans into broader privacy/data-subject-rights tooling beyond just the banner.
• Iubenda — pairs consent management with legal-document generation (privacy policy, terms), useful if you need both in one place.
• Termly — similar territory to Iubenda, policy generation plus a banner.
• TrustArc — enterprise-focused, deep configurability, similar positioning to OneTrust.
• Usercentrics — strong Consent Mode v2 support out of the box, positioned as an all-in-one platform since absorbing Cookiebot.
• Didomi — technically thorough, good documentation, popular with teams that want fine-grained control over consent categories.

Why the Choice Matters Less Than You'd Think

Every platform on this list, correctly configured, does the core job: shows a banner, records a choice, blocks non-essential cookies until consent is granted. The features that differentiate them — legal-document generation, data-subject-rights portals, enterprise SSO — are real, but they're not where tracking actually breaks.

What breaks is almost always the wiring between the CMP and Google Tag Manager: a trigger condition that doesn't match the CMP's actual consent event, a Consent Mode default that never got set, a tag that's supposed to wait for a category that was renamed in a CMP update six months ago and nobody noticed. The CMP itself passed every test it was designed for. The connection to your actual tags is the part nobody's watching.

What to Actually Check Before Committing to One

1. Consent Mode v2 support — confirm it sets ad_storage, analytics_storage, ad_user_data, and ad_personalization correctly, not just the older two-signal version.
2. How it signals consent to GTM — does it push to the dataLayer directly, fire native events, or both? This determines how your triggers need to be built.
3. Geo-targeting — if you serve visitors outside the UK, whether it can show different banners (or none) by region without needing a second platform.
4. How often it's updated — consent requirements shift, and a CMP that hasn't shipped an update in a while is a CMP whose Consent Mode implementation is quietly ageing.

Where CookieChest Fits

CookieChest doesn't compete on CMP features — we use Cookie-Script under the hood, white-labelled, because building consent-banner technology from scratch would mean competing with the ten platforms above at something they already do well. What we add is the part missing from every CMP on this list: independent, ongoing verification that the banner and your tags are still correctly wired together, not just on day one but every day after, through every CMP update and every GTM publish.

A CMP tells you it's installed. It doesn't tell you six weeks later that a GTM change broke the trigger that was supposed to respect it.