Landing-page SDK reference

The landing-page SDK is a small script (ES5, no dependencies) served from your tracking domain at /sdk.js. It keeps the click ID available on your landing site, joins Google Ads parallel-tracking clicks by gclid, records direct and organic visits, decorates links and fires conversions from the browser.

Install#

Add the script to every page of your landing site — in the <head> or before </body>:

<script async src="https://trackcrown.com/sdk.js" data-offer="OFFERCODE"></script>

Load the script once per page; a second copy does nothing.

How the click ID is found#

When the page loads, the SDK checks, in this order:

1. A click ID in the page URL — the data-param parameter, then click_id, transaction_id, tid (32 hex characters). It is used as is.
2. A Google click ID — gclid, gbraid or wbraid in the URL. The SDK asks the tracking domain (POST /lp) for the click recorded by the tracking template's background request — this is how parallel tracking is joined. If nothing is found, it falls back to a stored click ID.
3. A stored click ID from an earlier visit (local storage, else the atk_cid cookie).
4. Organic — with data-organic and an organic partner configured, a new organic click is recorded: sub1 = the source platform from the referrer (google, bing, facebook, x, referral or direct), sub2 = the referring host, sub3 = the landing path.
5. Direct — with data-offer, a new direct click is recorded for the offer (and data-aff).

Otherwise there is no click ID (ArcTrack.clickId() returns null). The /lp request times out after 5 seconds.

Storage#

A partner's click always wins: a visitor who later arrives through a partner link replaces the stored organic click. When the first click differs from the current one, conversions carry it as first_click_id; your workspace's attribution model (Settings → Conversion rules: last touch by default, or first touch) decides which is credited.

JavaScript API#

The SDK exposes one global object, window.ArcTrack. ArcTrack is a fixed technical name of the tracking engine — the same on every installation, whatever your brand — so your code never changes when the brand does. Calls made before the script has loaded are queued:

<script>
  window.ArcTrack = window.ArcTrack || [];
  ArcTrack.push(["conversion", { event: "sale", amount: "49.90", txid: "ORDER-1001", currency: "USD" }]);
  ArcTrack.push(function (clickId) { console.log("click", clickId); });
</script>
<script async src="https://trackcrown.com/sdk.js" data-offer="OFFERCODE"></script>

conversion()#

ArcTrack.conversion(params) requests https://trackcrown.com/px?js=1&click_id=…&… as an image. It sends:

• click_id (when known) and first_click_id (when it differs);
• offer = data-offer only when no click ID is known (direct and organic conversions), unless you pass offer/offer_id yourself. With a click ID no offer is sent — also not an offer/offer_id you pass — because the click names its offer, and a different offer would be refused with offer_id does not match the click;
• aff = data-aff, unless you pass aff/aff_id yourself;
• every other key of params as a query parameter — event, amount, txid, currency, adv1…adv5, email, coupon_code and so on (objects, functions and the keys click_id, token, js are skipped);
• a random r cache buster.

These are pixel conversions (method js): the offer's conversion method must allow pixels (any or pixel). Parameters: Conversion pixels.

Passing the click ID on#

The SDK rewrites links when the click ID is known, and again on every link click (so links added later are covered):

• a link whose href contains {click_id} (or %7Bclick_id%7D) gets the macro replaced;
• a link with a data-atk attribute gets click_id=<id> set — or the parameter named in data-atk (an existing value is replaced, a #fragment kept).

javascript:, mailto: and tel: links are never touched.

<a href="https://checkout.example.com/buy?ref={click_id}">Buy now</a>
<a href="https://app.example.com/signup" data-atk="aid">Sign up</a>

The /lp endpoint#

The SDK talks to POST https://trackcrown.com/lp. You can call it from your own code. CORS is open, no credentials are needed, and the body may be sent as text/plain (no CORS preflight).

Request body (JSON):

Answer: {"click_id": "…", "source": "…"}, decided in this order:

The direct click maps the page URL's query parameters onto the click like a tracking link (sub IDs, ValueTrack values, gclid). A click found by gclid is returned immediately, even while it is still being written to the reporting database.

Errors are JSON {"error": "…"}:

The SDK reports every failed /lp call on the browser console (console.warn, prefixed with the SDK object name ArcTrack:) with the HTTP status and error — for offer required with the hint to add data-offer="OFFERCODE" to the script tag — and ArcTrack.error() returns the same text. A timeout or network error is reported too. The page itself is never affected.

Example — parallel tracking on a shared brand domain, where the page only knows the gclid:

curl -s https://trackcrown.com/lp -H 'Content-Type: text/plain' \
  -d '{"gclid":"EAIaIQobChMI","url":"https://www.example.com/?gclid=EAIaIQobChMI"}'
# {"click_id":"0192f3c1a2b4e1f0c9d84b2a7e6f5d3c","source":"gclid"}

Clicks a Google Ads tracking template sends through the tracker store the gclid, gbraid and wbraid that auto-tagging adds to the landing page (the url= value), so templates never need {gbraid} or {wbraid} tags.

Privacy#

The SDK stores only the random click IDs (atk_cid, atk_fcid) on your domain. Mention them in your cookie notice and ask for consent where your law requires it.

See also: Parallel tracking · Final URL suffix + SDK.