What is the AMP_MKTG_ cookie?
AMP_MKTG_ belongs to the family of cookies used by Amplitude, a user behavior analytics service for websites and apps, owned by Amplitude, Inc. The AMP_MKTG_ prefix is followed by an identifier specific to the project or Amplitude instance configured for the site.
The cookie is typically set by the Amplitude JavaScript tracking library, whether installed directly on the site or loaded through a tag manager, when a visitor loads a page and the analytics script runs.
What data it stores
The cookie generally stores a unique identifier associated with the visitor or session, which Amplitude uses to link on-site events and actions to a persistent user profile. The exact value format and length are not publicly documented in detail and may vary depending on the project configuration.
Data collected through this cookie is sent to Amplitude's servers, typically outside the site's own jurisdiction, depending on the hosting region (EU or US) chosen by the Amplitude account administrator.
What it is used for
The stated purpose of the AMP_MKTG_ cookie relates to marketing attribution – it helps Amplitude recognize a returning visitor and link their actions across multiple sessions to the traffic source or campaign that brought them to the site.
For the site owner, this type of cookie provides aggregated insight into marketing channel effectiveness and user behavior across visits, used in product analytics reports.
Does it require consent?
Under CookieFix's classification, AMP_MKTG_ falls under the statistics (analytics) category. Because it involves long-term tracking of visitor behavior (duration of about one year) and marketing attribution, this cookie is not strictly necessary for the site to function, so it requires the user's prior consent under GDPR and the ePrivacy Directive.
The site owner must disclose this cookie in the cookie policy, classify it correctly under the statistics/marketing category in the consent banner, and ensure the Amplitude script does not run before consent is obtained.
How to block or delete AMP_MKTG_
A visitor can delete or block the AMP_MKTG_ cookie directly from browser settings (per-site cookie management) or by using tracker-blocking extensions. Blocking this cookie does not affect the site's core functionality, only Amplitude's ability to collect analytics data.
- Site owners can automatically block the Amplitude script until consent is given, using a CMP such as CookieFix, which by default stops statistics/marketing scripts and activates them only after the visitor explicitly accepts.
- Alternatively, the Amplitude script can be manually configured to load only when a consent signal is present (for example via Google Consent Mode or custom logic).
Frequently asked questions
It doesn't store sensitive personal data as such, but it enables long-term tracking of visitor behavior, which is why it's classified as a statistics/marketing cookie requiring consent.
It's set by the Amplitude analytics script, embedded directly on the site or loaded through a tag manager, when a visitor loads a monitored page.
Its typical duration is around one year, allowing Amplitude to recognize a returning visitor over the long term.
Yes, as a long-duration statistics/marketing cookie, it falls under the categories requiring prior visitor consent under GDPR and ePrivacy legislation.