What is the AMP_ cookie?
AMP_ is a cookie name prefix used by Amplitude, a product and user behavior analytics platform used by websites and apps to understand how visitors interact with their pages and features. The full cookie name continues after the prefix with a unique identifier generated for each Amplitude project connected to the site.
The cookie is set by Amplitude's JavaScript script (its analytics SDK), included on the site directly by the administrator or through a tag manager. It appears in the browser as soon as the Amplitude script loads and starts tracking visitor activity, typically on the first page visit.
What data it stores
The AMP_ cookie typically stores a unique device or session identifier generated by Amplitude, used to recognize the same visitor on later visits and to group recorded events (clicks, page views, in-app actions) under the same analytics profile.
The exact value varies depending on each Amplitude project's configuration and may include encoded session information; no fixed internal format is publicly documented. Data collected through this cookie is sent to Amplitude's servers for processing and display in the site's analytics dashboard.
What it is used for
For the provider (Amplitude), the cookie enables building a behavioral profile of the visitor across multiple sessions, which is essential for the platform's core features: conversion funnels, retention, user segmentation, and product analytics.
For the site administrator, this data translates into reports on how users navigate, where they drop off in a process (such as checkout), and which features are used most — information used for product and marketing decisions, not for delivering an essential site service.
Does it require consent?
In CookieFix's classification, AMP_ falls under the statistics (analytics) category. Since it is used for measurement and behavioral profiling, it is not strictly necessary for the site to function, so it falls under the ePrivacy Directive (transposed in Romania via Law 506/2004) and the GDPR: the visitor's prior, freely given consent is required before this cookie is set.
- The site administrator must declare the AMP_ cookie in the cookie policy, including its purpose, provider, and duration.
- The Amplitude script must be blocked until explicit consent for the statistics category is obtained.
- A genuine option to refuse must be offered, as easy to use as the option to accept.
How to block or delete AMP_
A visitor can manually delete or block this cookie from browser settings (Chrome, Firefox, Edge, Safari), through per-site cookie management options, or by using private browsing mode to avoid long-term storage.
For the site administrator, correctly blocking it before consent is achieved through a Consent Management Platform such as CookieFix, which automatically stops the Amplitude script from running until the visitor chooses to accept the statistics category, avoiding setting the cookie without a legal basis.
Frequently asked questions
It's an HTTP cookie set by Amplitude's analytics script, used to identify visitors and track their behavior on a site.
It isn't malicious, but it can qualify as personal data when it allows a visitor to be identified, which is why it requires consent.
Its typical duration is 1 year, after which it expires automatically unless renewed by a new visit.
Yes, since it's a statistics cookie, it requires the visitor's prior consent under the GDPR and Law 506/2004.