The Page Click ID (atclid) 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.
How the Page Click ID relates to the Click ID
Section titled “How the Page Click ID relates to the Click ID”The atclid is the root that a Click ID extends. A full Click ID is 34 characters — the atclid plus characters that identify a specific element (a link, form, or cart). So one page load has a single atclid, but each trackable element on it gets its own Click ID.
Notes on the Page Click ID
Section titled “Notes on the Page Click ID”PageView is the only standard event that does not generate a Click ID by default. In Shopify, the atclid is carried into the order via note_attributes.__atclid and the line-item properties._atclid, 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?
The atclid is the 30-character Click ID for the whole page session, generated once when the page loads. The click_id is 34 characters: it extends the atclid with characters that identify a specific element, so each link, form, or cart gets its own value.