Google Analytics 4

For GA4, PixelFox injects the gtag snippet (unless your site already loads one) and fires mapped e-commerce events - view_item, add_to_cart, begin_checkout, purchase, search, generate_lead, sign_up - from the browser.

Credentials

Field	Where to find it
Measurement ID	GA4 Admin → Data streams → your web stream → the `G-XXXXXXX` id top-right. (screenshot placeholder)
API secret	Same data stream → Measurement Protocol API secrets → Create → copy the secret value. (screenshot placeholder)

Event routing

Unlike Meta and TikTok, GA4's Measurement Protocol has no event deduplication - a browser event and a server event for the same purchase count twice. So exactly one side fires the funnel, chosen by the destination's Event routing:

Mode	Browser gtag	Measurement Protocol
Auto (default) / Browser	loaded by the tag, fires every mapped event	only server-only events, and only with Send server-only events on
Server	not loaded for GA4	every conversion

A connected GTM container always forces browser routing - its GA4 tags cannot be told to stand down. Server routing needs an API secret.

Server-only events are the ones that never had a browser counterpart: purchases sent by the WooCommerce, Laravel and Python helpers, and COD deliveries. PixelFox recognises them by the absence of the browser tag's viewport fields (or an explicit $action_source other than website), so a browser event is never sent twice even with the toggle on.

What the server sends

Measurement Protocol events carry what GA4 needs to attribute and report them like a browser hit:

client_id from the visitor's _ga cookie ($ga_client_id), or a stable synthetic id derived from the device id when the cookie is absent
session_id from the _ga_<stream> cookie ($ga_session_id), so the event joins the browser session instead of (not set); server-only events get a 30-minute bucket
user_id when identity stitching has resolved the visitor
value, currency, transaction_id (always present on purchase), shipping, tax, coupon
items[] with item_id, item_name, price, quantity, item_category, item_brand, item_variant - from the event's line items, or the single product
search_term on search, page_location, page_title, page_referrer

Pageviews are never sent server-side; the browser tag owns them.

Validate before you trust it

The production endpoint answers 204 to anything that parses as JSON - it validates nothing. To check a payload, prefix the API secret with DEBUG_ (e.g. DEBUG_abc123DEF456). PixelFox then posts to Google's validation endpoint and surfaces every validationMessages entry on the destination card's delivery state. Nothing is recorded in GA4 while the prefix is in place; remove it to go live.

Verify

GA4 → Admin → DebugView shows browser events live. Server-side events show in Realtime after a server-only purchase, attributed to the same session as the browser hits when the visitor's _ga_<stream> cookie was present.