Tracking & analytics, in plain words.

Comparing two versions of a page or ad to see which performs better, by splitting traffic between them and measuring results.

A browser tool or extension that blocks scripts and trackers. Ad blockers stop client-side tags like the Meta pixel from firing, hiding a share of your conversions.

Apple’s iOS feature that asks users whether an app may track them. Most decline, which is why the Meta pixel lost a large share of its data after iOS 14.

Assigning credit for a sale to the marketing touchpoints that led to it. Broken tracking causes lost or “unassigned” attribution, so you can’t tell which ads work.

Tracking that runs in the shopper’s browser. It’s easy to set up but vulnerable to ad blockers, ITP and privacy settings, so it loses 30–50% of conversions.

Google’s framework for adjusting how tags behave based on a visitor’s cookie consent. With it, analytics only run once the visitor agrees.

A completed action that matters to your business — most often a purchase, but also a sign-up, lead or add-to-cart.

Meta’s Conversions API — a server-to-server channel for sending conversions to Meta that ad blockers and iOS restrictions cannot intercept, unlike the browser pixel.

A small file a website stores in the browser to remember things like sessions and preferences. Privacy rules shorten or block many tracking cookies.

Cost per Acquisition — the average amount you pay to win one conversion. Missing conversions make CPA look worse than it really is.

Cost per Click — the amount an advertiser pays each time someone clicks an ad.

Cost per Mille — the cost of one thousand ad impressions.

Click-Through Rate — the percentage of people who click an ad after seeing it.

A Google Ads feature that sends hashed customer data (email, phone, name) with a conversion to improve matching, recovering conversions on iOS and privacy-restricted traffic.

Counting a conversion once when both a browser tag and a server-side event report it, by matching a shared event ID. Prevents double-counted sales.

A unique identifier attached to an event so platforms can deduplicate it. For purchases it’s often derived from the order reference, so reloads don’t double-count.

A hashed reference to a customer sent to Meta, helping it match conversions to a person across devices and sessions.

Meta cookies: _fbc stores the ad click identifier (from fbclid) and _fbp identifies the browser. Server-side tracking can construct and forward them for better matching.

Data you collect directly from your own customers on your own domain. It’s more durable and privacy-friendly than third-party data, and central to server-side tracking.

Google Analytics 4 — Google’s analytics platform. Sent server-side, it reports accurate sessions and revenue that reconcile with your real orders.

Google click identifiers used for iOS app-to-web and web-to-app journeys, where the standard gclid isn’t available. Needed to attribute iOS conversions.

The Google Click Identifier appended to ad clicks. Capturing and sending it back lets Google attribute a conversion to the exact click that earned it.

Google’s advertising platform. Clean, server-side conversions and Enhanced Conversions give its Smart Bidding accurate data to optimise on.

Google Tag Manager — a tool for managing tracking tags without editing site code. It runs in the browser unless paired with a server-side container.

Turning personal data into an irreversible fingerprint with SHA-256 before sending it. Platforms can match on the hash without ever receiving the raw value.

Apple’s 2021 privacy update (App Tracking Transparency + ITP) that broke much of the Meta pixel and shortened tracking cookies — the main reason stores switched to server-side.

Intelligent Tracking Prevention — Safari’s feature that limits and shortens cookies, causing client-side analytics to lose data and fragment sessions.

The “G-” identifier of a GA4 data stream that tells events which property to report to.

Meta’s browser tracking tag. iOS restrictions and ad blockers strip it of many events, which the Conversions API recovers server-side.

Personally Identifiable Information — data like email, phone or name. PrestaSignal hashes PII on your server before it ever leaves.

Showing ads to people who already visited your store. Dynamic remarketing needs accurate product and page data, which server-side tracking keeps populated.

Return on Ad Spend — revenue earned per unit of ad spend. Under-reported conversions make profitable campaigns look unprofitable.

A server-side Google Tag Manager container that receives events on your own infrastructure and forwards them to platforms — beyond the reach of ad blockers.

Tracking that sends events from your own server instead of the browser. It survives ad blockers and iOS restrictions, recovering conversions client-side tags lose.

A single visit to your store. Inconsistent client-side tags inflate or fragment sessions; server-side tracking keeps the real session intact.

Google’s automated bidding that optimises toward conversions. It’s only as good as the conversion data it receives — incomplete data trains it poorly.

A unique ID for an order, sent with the purchase event so the same sale is counted once even if the confirmation page reloads.

A persistent identifier for a logged-in customer that lets GA4 stitch their activity across devices.

Tags added to a URL (utm_source, utm_medium, etc.) that tell analytics where a visitor came from.