Page Click ID

The 30-character click ID for the current page session, generated by the Tracking Tag on page load — the root a Click ID extends to 34.

identifier Also known as: page click id

The Page Click ID is a 30-character click ID for the current page session. The Tracking Tag generates it when a page loads; it is not tied to a specific element. It is commonly called the atclid, after the URL parameter that carries its value — but the parameter is the name, and the Page Click ID is the value.

How the Page Click ID relates to the Click ID

The Page Click ID is the root that a Click ID extends. A full Click ID is 34 characters — the Page Click ID plus characters that identify a specific element (a link, form, or cart). So one page load has a single Page Click ID, but each trackable element on it gets its own Click ID.

Notes on the Page Click ID

PageView is the only standard event that does not generate a Click ID by default. In Shopify, the Page Click ID is carried into the order in the note_attributes.__atclid and line-item properties._atclid fields, so the server-side order matches back to the browser session.

Frequently asked questions

FAQ was last reviewed on 2026-06-23

What is the difference between atclid and click_id?

They are different kinds of thing: `atclid` is a URL parameter name, and the click_id is an identifier value. The value the atclid parameter carries is the Page Click ID — 30 characters for the whole page session, generated once when the page loads. A Click ID is 34 characters: the Page Click ID plus characters that identify a specific element, so each link, form, or cart gets its own value.

Related terms

Click IDThe 34-char identifier the Page Click ID extendsProperty IDForms the prefix of the page click IDAutoTagAppends the Click ID (built from the Page Click ID) to links and formsClient IDGenerated alongside the Client ID when the page loads