What is the Google tag (gtag.js)?
The Google tag, gtag.js, is a single piece of code that connects your website to Google's products, GA4 and Google Ads, from one snippet. It is Google's simplest way to get measurement running without a separate tag-management tool.
What it does
You place one Google tag on your site, keyed to a tag ID, and it can send data to GA4 and Google Ads together. It handles page views and can fire events and conversions directly. For a simple setup, it is all you need to start measuring.
Google tag vs Google Tag Manager
- Google tag (gtag.js): code you edit on the site; simple, but every change means touching the site.
- Google Tag Manager: a container you manage from a web UI, add and change tags without redeploying the site, and gate them with consent more easily.
Which should you use
For a basic site with one or two tags, the Google tag is fine. The moment you have several tags, custom events, a data layer or real consent needs, GTM is worth it, you manage everything in one place and stop editing site code for every tweak. Most businesses past the starter stage end up on GTM.
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