The dataLayer is a JavaScript array on the page (window.dataLayer) that a website uses to hand structured information to a tag manager. Your site pushes objects into it — an event name plus its parameters, such as a purchase with its order value and item list — and Google Tag Manager reads those objects to fire tags and populate variables.
dataLayer, in full →Server-side tagging routes tracking data through a server you control instead of sending it from the browser straight to each vendor. The browser makes one request to your own endpoint; that server container then decides what to forward to GA4, Meta, Google Ads, or TikTok, and what to strip out first.
Server-side tagging, in full →An event parameter is a named value sent alongside an analytics event to describe it — value and currency on a purchase, item_name on a product view, method on a login. In GA4, parameters are the unit of detail: the event says what happened, the parameters say which one, how much, and in what context.
Event parameter, in full →E-commerce tracking is the set of standardised events that describe a shopping journey — view_item, add_to_cart, begin_checkout, purchase — each carrying an items array plus a value and currency. GA4, Meta, and Google Ads all expect this shape, so getting it right once feeds every downstream platform.
E-commerce tracking, in full →Google Tag Manager (GTM) is a free tool that lets you deploy and change tracking code on a website without editing the site's source. You install one GTM snippet once, then add, edit, and remove tags — GA4, Meta Pixel, Google Ads, TikTok — from a web interface, and publish them to the live site in seconds.
Google Tag Manager (GTM), in full →A GTM container is the versioned bundle of tags, triggers, and variables that Google Tag Manager publishes to one website or app. It is identified by an ID in the form GTM-XXXXXXX, which appears in the snippet you install on the site.
GTM container, in full →A GTM trigger is the condition that decides when a tag runs. Triggers listen for something on the page — a page view, a click, a form submission, a scroll depth, or a custom dataLayer event — and fire every tag attached to them when their conditions all match.
GTM trigger, in full →Key events are the GA4 events you have marked as business-critical — purchases, sign-ups, qualified leads. Google renamed this concept from "conversions" to "key events" in 2024; the word "conversions" in GA4 now refers to ad-platform conversions imported from Google Ads, so the two terms are no longer interchangeable.
GA4 key events, in full →A Measurement ID is the identifier of a GA4 data stream, formatted as G-XXXXXXXXXX. It tells the GA4 tag which property and stream to send hits to, and it is the value you paste when configuring GA4 in a tag manager.
Measurement ID, in full →The Measurement Protocol is GA4's HTTP API for sending events to a property directly from a server, without a browser. It is how offline conversions, subscription renewals, refunds, and server-confirmed purchases get into analytics at all.
Measurement Protocol, in full →The Meta Conversions API (CAPI) sends conversion events to Meta from your server instead of from the browser. It runs alongside the Meta Pixel rather than replacing it — the pixel keeps firing in the browser, the server sends the same events, and Meta deduplicates the pair using a shared event ID.
Meta Conversions API (CAPI), in full →A tracking pixel is a small piece of code an advertising platform gives you to place on your site so it can attribute conversions back to its ads and build retargeting audiences. Modern pixels — Meta Pixel, TikTok Pixel, LinkedIn Insight Tag — are JavaScript snippets rather than literal 1×1 images, though the name stuck.
Tracking pixel, in full →Enhanced conversions is a Google Ads feature that improves conversion measurement by sending hashed first-party customer data — email, phone, name, address — alongside each conversion. Google matches the hashes against signed-in Google accounts to recover conversions that cookie-based tracking missed.
Enhanced conversions, in full →An attribution window is the period after an ad interaction during which a resulting conversion is still credited to that interaction. Platforms use different defaults — Meta commonly 7-day click and 1-day view, Google Ads 30-day click — which is the main reason two dashboards report different numbers for the same sales.
Attribution window, in full →UTM parameters are query-string tags appended to a link — utm_source, utm_medium, utm_campaign, utm_term, utm_content — that tell analytics where a visitor came from. They are read directly from the URL, so they work without any cooperation from the referring site.
UTM parameters, in full →Consent Mode v2 is Google's framework for adapting how its tags behave to a user's consent choices. It adds two signals — ad_user_data and ad_personalization — to the original analytics_storage and ad_storage pair, and since March 2024 Google has required them from advertisers serving EEA and UK users.
Consent Mode v2, in full →A Consent Management Platform (CMP) is the tool that presents a cookie or privacy banner, records each visitor's choice, and publishes that choice to the rest of your tracking stack. Common examples include Cookiebot, OneTrust, Osano, Termly, Iubenda, and Shopify's built-in privacy banner.
Consent Management Platform (CMP), in full →A first-party cookie is set by the domain the visitor is actually on; a third-party cookie is set by a different domain loaded in the page. Browsers treat the two very differently — Safari and Firefox block third-party cookies outright, and Safari's Intelligent Tracking Prevention caps first-party cookies written by JavaScript at seven days.
First-party cookie, in full →Hashed identifiers are customer details — email address, phone number, name — converted with a one-way hash function, normally SHA-256, before being sent to an advertising platform. The platform can compare hashes to find the same person in its own data, but cannot reverse a hash back to the original value.
Hashed identifiers, in full →PII leakage is the accidental transmission of personally identifiable information — email addresses, phone numbers, names, order-level customer details — into an analytics or advertising platform that is not permitted to receive it. It usually happens through URL query parameters, page titles, or dataLayer values that were never audited.
PII leakage, in full →Tag drift is the gradual divergence between the tracking you believe is configured and the tracking your live site is actually running. It accumulates from site redesigns that break selectors, plugin updates that remove snippets, consent changes that suppress tags, and container edits nobody documented.
Tag drift, in full →A container audit is a systematic review of everything inside a tag management container — every tag, trigger, and variable — checking for duplicates, tags that never fire, missing consent settings, PII exposure, and unnecessary page weight. It answers "what is actually deployed and is any of it wrong".
Container audit, in full →A tracking plan is the documented specification of every event your site should send, with each event's required parameters, their types, and the business question the event exists to answer. It is the contract that makes it possible to say a tracking implementation is wrong rather than merely different.
Tracking plan, in full →Synthetic monitoring for tracking means running a scripted browser through your key user journeys on a schedule — view a product, add to cart, complete checkout — and asserting that the expected analytics events fire with the expected parameters. It catches broken tracking before real users generate the missing data.
Synthetic monitoring (for tracking), in full →The free auditor runs 13 checks against any URL — Consent Mode v2 signals, PII exposure, duplicate pixels, script weight — and returns a 0–100 score. No signup.
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