What is twclid?

Who adds it

X generates it for ad clicks and passes it in the landing page URL. X's Conversions API docs tell advertisers to read it from the query string.

What it means

The visit came from an ad on X. Advertisers send the value back to X with conversion events to match them to the click.

What to do with it

X recommends parsing it whenever it's present and storing it with the conversion. The referrer for the same visit is usually t.co.

How Vireo shows it

Vireo doesn't store click IDs, in the free plugin or in Pro.

In the free plugin, Vireo drops the query string from page addresses, keeping only a few WordPress ones such as p and page_id, so a tagged URL counts as the same page as the untagged one. The visit is counted under the referrer it arrived with.

See Referrers and sources in the docs.

Sources

The Click ID should be parsed out of the query string parameter twclid when it is available after the user navigates to the destination website.

Web conversions - X Ads API documentation

Always parse the twclid value when it is present in the URL query parameters.

Web conversions - X Ads API documentation