Google Consent Mode v2: what it is and how to apply it on your website

If you use Google Analytics, Google Ads or Google tags on your website and have visitors from the European Economic Area, Consent Mode v2 affects you. It is how your website tells Google what each visitor has decided about cookies.

What Consent Mode is

Consent Mode is a mechanism that lets Google tags adjust their behaviour according to the user’s consent. If the visitor accepts, they measure normally; if they reject, they do not use cookies to identify them and send only signals without identifiers.

The four parameters of v2

• ad_storage: allows storing advertising-related cookies.
• analytics_storage: allows storing analytics cookies.
• ad_user_data: allows sending user data to Google for advertising purposes.
• ad_personalization: allows using data for personalised advertising or remarketing.

The last two are the novelty of version 2. Google requires them to keep personalised advertising and conversion measurement features for EEA visitors.

How it works in practice

1. Before the visitor decides, all parameters are set to “denied” by default.
2. The cookie banner shows the options.
3. When the user chooses, your website updates the parameters (for example analytics_storage: granted).
4. Google tags behave according to those values.

It is essential that the default value is applied before the tags load. Otherwise they have already run without permission.

Basic or advanced

• Basic mode: Google tags do not load until there is consent. It is the most conservative option.
• Advanced mode: tags always load, but with minimal signals without identifiers if there is no consent. Google uses models to estimate lost conversions.

The choice must be consistent with your cookie policy and your legal adviser’s criteria.

What happens to your data

With visitors who reject, you will lose part of the measurement. Google’s conversion modelling can estimate some of what is missing, but:

• It is not magic: it needs a minimum volume of data.
• You will see differences between what Google measures and your real sales. Always compare with your CRM or shop.

How to implement it

• With a consent management platform (CMP) compatible with Consent Mode.
• With custom development that sets the default values and updates them when the user decides.
• Check with the Google Tag Manager preview tool or browser developer tools that the signals go out as you expect.

Common mistakes

• A banner that only shows “Accept” or hides rejection.
• Loading tags before consent.
• Not recording the user’s choice.
• Forgetting the two new v2 parameters.

All of this is technical, but it is solved once and maintained. At IMPERA we leave your website compliant and with measurement working. Legal texts should always be validated with your adviser.