TL;DR
The Data Layer is a JavaScript array (window.dataLayer) that passes structured data from your website to GTM. Push data using dataLayer.push({event: 'event_name', key: 'value'}). GTM reads this data via Data Layer Variables and uses it in tags and triggers. Common implementations: e-commerce transactions (order value, products, currency), form submissions (form name, field values), user properties (logged-in status, user type), and page metadata (page category, content group). Plan your Data Layer schema before implementation — document every event name, parameter, and expected value. Consistent naming is critical.
Overview
The Data Layer is a JavaScript array (window.dataLayer) that passes structured data from your website to GTM. Push data using dataLayer.push({event: 'event_name', key: 'value'}). GTM reads this data via Data Layer Variables and uses it in tags and triggers. Common implementations: e-commerce transactions (order value, products, currency), form submissions (form name, field values), user properties (logged-in status, user type), and page metadata (page category, content group). Plan your Data Layer schema before implementation — document every event name, parameter, and expected value. Consistent naming is critical.
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Frequently asked
Questions & answers
How long does setup take?
Most configurations take 10-30 minutes. Full campaign setup and ongoing optimisation is a continuous process.
What budget should I start with?
Start with enough to generate at least 50 conversions per week for the platform's algorithm to learn effectively. This varies by industry and CPA.
When should I expect results?
Allow 2-4 weeks for the initial learning phase. Meaningful performance trends typically emerge after 30 days of consistent spending.
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