What is the `datr` Cookie?

Set by Facebook Messenger (Chat Plugin) (Meta Platforms, Inc.). Expires after 2 years.

Purpose

Browser identifier set by Facebook to prevent spam and detect fraudulent account activity. Also used for ad targeting.

Set by any Facebook widget or plugin, not just Messenger. Enables cross-site tracking for ad targeting.

Cookie Name	`datr`
Service	Facebook Messenger (Chat Plugin)
Provider	Meta Platforms, Inc.
Category	Marketing / Advertising
Duration	2 years
Consent Required	Yes — requires explicit opt-in

Marketing cookies are used to track visitors across websites to display relevant advertisements. Consent is required under GDPR.

Under GDPR and the ePrivacy Directive, the datr cookie requires explicit user consent before it can be set. This means:

The cookie must not be set when a user first visits your site — not even for a fraction of a second
A consent banner must be displayed, and the user must actively accept analytics/marketing cookies
If the user rejects or ignores the banner, this cookie must remain blocked
The cookie must be listed in your cookie policy with its name, purpose, and retention period
Users must be able to withdraw consent at any time, which must also remove or invalidate this cookie

Block it by default — configure your Consent Management Platform (CMP) or tag manager to prevent Facebook Messenger (Chat Plugin) from loading until the user accepts marketing cookies.
Include it in your consent categories — map it to the "Marketing / Advertising" category in your CMP configuration.
List it in your cookie policy — document the cookie name, purpose, provider (Meta Platforms, Inc.), and expiry (2 years).
Sign a DPA — ensure you have a Data Processing Agreement with Meta Platforms, Inc. covering their use of data collected via this cookie.
Verify it works — in an incognito browser, reject cookies and confirm datr is not set.

Scan your website to see every cookie it sets, whether they're blocked before consent, and get a full GDPR compliance report.