Google Consent Mode v2 is Google's framework for adjusting how Google Ads, GA4, and other services behave based on user consent. Mandatory for EEA, UK, and Swiss traffic since March 2024 for anyone using remarketing or conversion measurement. It uses four parameters — ad_storage, analytics_storage, ad_user_data, ad_personalization — in Basic mode (tags don't fire until consent) or Advanced mode (tags fire but send cookieless pings when denied, enabling conversion modelling). Consent Mode v2 doesn't replace GDPR consent — it only adjusts what Google does with the consent signal you send. Setting parameters to "granted" by default is a common compliance failure.