Skip to main content
Cookie reference · Pinterest Tag

The _pin_unauth cookie

A Pinterest Tag cookie with a UUID for visitors Pinterest can't match to a Pinterest user, used for ad measurement.

_pin_unauth at a glance

Cookie name
_pin_unauth
Vendor
Pinterest Tag
Category
Advertising
Party
First-party
Typical duration
1 year
Set on
.<your-domain>
Value format
Contains a UUID, commonly base64-encoded (encoding not documented by vendor)
Name match
Exactly _pin_unauth

What the _pin_unauth cookie does

The Pinterest Tag sets _pin_unauth as a first-party cookie when Pinterest can't match the visitor to a Pinterest user. It contains a unique UUID used to group that visitor's actions across pages for ad measurement.

Pinterest describes it as persistent for one year from when the tag is installed. Its third-party counterpart on Pinterest's own domain is _pinterest_ct_ua.

What TagPipes observed

0.41%

of sites scanned set it (167 of 41,162)

365 days

median observed lifetime

TagPipes scanned 41,162 public websites between August 11, 2026 and September 13, 2026, loading up to three pages per site in a real browser as a first-time visitor. _pin_unauth was present on 167 of them.

It was set as a first-party cookie on 125 sites and as a third-party cookie on 42. A site can count in both. Where it was stored as a persistent cookie, the median lifetime we recorded was 365 days.

Often found alongside

Percentage of sites with _pin_unauth where the other cookie was also present.

Technologies detected on the same sites

  • Pinterest Tag on 99% of them (0.46% of all sites scanned)
  • Google Analytics on 99% of them (55% of all sites scanned)
  • Meta Pixel on 92% of them (13% of all sites scanned)
  • DoubleClick on 85% of them (11% of all sites scanned)
  • Google Ads on 83% of them (12% of all sites scanned)

Aggregate figures across all sites scanned. Websites of TagPipes customers are excluded, no individual site is named, and cookie values are never read or stored. Snapshot dated September 13, 2026.

How to check for _pin_unauth on a website

  1. Open the site in Chrome, then open DevTools (F12, or Cmd+Option+I on a Mac).
  2. Go to the Application tab and expand Cookies in the left panel.
  3. Select each domain listed there and look for _pin_unauth. The Expires column shows when it will be deleted.
  4. If it is not there, reload the page. Many cookies are only set after a tag has loaded, and some only after a visitor has made a consent choice.

Sources

Purpose, duration and value format checked against the vendor documentation above on . The figures under What TagPipes observed are TagPipes scan data from September 13, 2026, not values documented by the vendor. Vendors change their cookies, and sites can configure their own names and lifetimes. Browse all cookies.

Know every cookie your own site sets

TagPipes Pulse identifies the cookies dropped on your site and flags unclassified or miscategorized ones. Shield builds your cookie declaration from a real scan rather than a questionnaire.

See Pulse See Shield

TagPipes monitors, configures and reports. It does not determine legal compliance and does not provide legal advice. Output is informational and reflects observed state at the time of observation. Rawsoft's expertise is technology, not law; please confirm any regulatory interpretation with your own counsel.