What is the `amplitude_id_*` Cookie?

Set by Amplitude (Amplitude, Inc.). Expires after 10 years.

Purpose

Persistent device identifier used by Amplitude analytics to track users across sessions.

One of the longest-lived analytics cookies. Requires explicit consent.

Cookie Details

Cookie Name	`amplitude_id_*`
Service	Amplitude
Provider	Amplitude, Inc.
Category	Analytics
Duration	10 years
Consent Required	Yes — requires explicit opt-in

Category: Analytics

Analytics cookies help website owners understand how visitors interact with websites by collecting and reporting information anonymously. Consent is required under GDPR.

GDPR Requirements

Under GDPR and the ePrivacy Directive, the amplitude_id_* 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

How to Handle This Cookie

Block it by default — configure your Consent Management Platform (CMP) or tag manager to prevent Amplitude from loading until the user accepts analytics cookies.
Include it in your consent categories — map it to the "Analytics" category in your CMP configuration.
List it in your cookie policy — document the cookie name, purpose, provider (Amplitude, Inc.), and expiry (10 years).
Sign a DPA — ensure you have a Data Processing Agreement with Amplitude, Inc. covering their use of data collected via this cookie.
Verify it works — in an incognito browser, reject cookies and confirm amplitude_id_* is not set.

Other Amplitude Cookies

Cookie	Category	Duration
amplitude_session_id_*	Analytics	Session

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