Get tracking metadata for a user

Get the custom tracking metadata from a user's most recent impression on a tracking link.

Metadata is captured from the query string of the shared short link (https://www.fanvue.com/<handle>/fv-3?campaign=spring_launch), using plain query parameters rather than the metadata[<key>] syntax checkout links use. Every non-reserved parameter is captured as-is, trimmed to 10 keys and 500 characters per value; over-limit input is silently trimmed rather than rejected.

Only the most recent impression is returned, and metadata is never merged across clicks: a later click replaces the previous values wholesale, and a later click with no query parameters returns null.

Returns 404 when the link is not one of the creator's, and 200 with metadata: null when the user has no attributed impression carrying usable metadata.

See the tracking links guide for the full mechanism, limits and worked examples.