--- title: Track customers in ODP slug: data-platform/docs/track-customers-in-odp docTags: createdAt: 2026-08-10T12:05:17.000Z --- Optimizely Data Platform (ODP) tracks visitors using browser cookies. When a visitor lands on your website, ODP checks for an existing tracking cookie. If one does not exist, ODP associates a cookie with that visitor and registers their on-site behaviors (like page views) moving forward, resulting in identity resolution and event collection. ## Cookie types There are two types of cookies: first-party cookies and third-party cookies. To enable event collection and user resolution, ODP stores first-party cookies specific to the brand’s website. - **First-party cookies** – Stored by the domain the customer visited. - **Third-party cookies** – Set by another domain, such as an ad server or ad platform engaging in cross-site tracking or retargeting of website visitors with ads or an on-site service (like a chat or login feature). The ODP JavaScript tag uses the following first-party cookies: - **ztsrc** – The last referrer; the location from which the customer accessed your site (for example, another website, Google, and so on). Expires after 60 days. - **z\_idsyncs** – Tracks IDs for the site visitor. Expires after 2 years. - **zaius\_web\_content** – Tracks web content that the visitor sees. Expires after 365 days. - **zaiusPushSubscribeDismissedUntil** – Stores the timestamp of when the push notification will display to the user.  Expires after 30 days. - **zaiusPushSubscribePopped** – Stores the timestamp of when the subscription pop-up last displayed to the user. Expires after 30 days. - **z\_customer\_id** – Stores the main ID used to identify the customer in ODP. Expires after 2 years. - **submittedWebContents** – Stores the data a visitor submits from a web form. Expires after 365 days. - **vuid** – Tracks the visitor UUID. If the customer ID is known, the VUID matches that ID. Expires after 2 years. - **zaius\_web\_push** – Web push tokens. Expires after 180 days. ## How ODP tracks and identifies customers You must [implement the ODP JavaScript tag](docId\:XIk4SqG8AEP3aCy05gIEB) on your site for ODP to track and identify customers. ODP first tracks and builds customer profiles for anonymous customers (those who are only identified by a tracking cookie). Once a customer provides identifiable information, ODP performs user resolution to create a more specific customer profile. For customer identity and resolution information, see [Overview of customer identity and resolution](docId\:Ctmpf0RC-3DhpfFdJEXTG). ### ODP JavaScript tag - ODP only tracks visitors if you have the [ODP JavaScript tag](docId\:XIk4SqG8AEP3aCy05gIEB) implemented on your site. - ODP connects page views to an identified customer if they click a link in a tracked email (legacy) that directs to a page with the ODP JavaScipt tag installed. ### Anonymous tracking - ODP tracks visitors, using first-party cookies, before they become a known customer. - When a visitor fills out a web embed or modal, ODP associates their previous anonymous page views based on their tracking cookie. If a customer in ODP already has that email address, ODP identifies this visitor as the customer. ### User resolution - ODP uses customer identifiers, such as a customer's email address and the VUID included in a customer's cookie, to determine which events are associated with the customer and if events from "different" visitors should be merged. - If a visitor deletes their cookies, ODP considers them a new visitor and assigns them a new cookie. However, ODP automatically applies user resolution and merges submissions from the same email address, even if different cookies were associated with those submissions. - If a customer uses a different browser or blocks cookies and does not provide identifiable information (such as email address or login information) in their subsequent visits, ODP counts them as multiple unique visitors. - If multiple people share a single computer and browser, their submissions result in unique customer profiles if they use a unique customer identifier (such as an email address). The profile associated with the most recent submission inherits the shared browser cookie/VUID, and ODP incorporates all events into that profile until another high-confidence submission from one of the "secondary" users occurs. ### Effect on email campaigns - ODP can only send email campaigns to identified customers, such as behavioral campaigns like cart abandonment. ODP qualifies someone for a cart abandonment campaign if they add a product to their cart and do not complete a purchase. However, if ODP cannot associate the event with a known customer email address through an identifier like their browser cookie, it does not send an email. You might observe more cart abandonment events than cart abandonment email sends. ## Privacy concerns The privacy and security scrutiny that third-party cookies face does not impact ODP functionality as it exists today. For more information about compliance and consent, see this [group of articles](docId\:BPGNJNLTdxui8KXybdSyO). - **Google Chrome’s SameSite update in February 2020** – Impacts access to third-party cookies through non-secure connections and requires the third-party cookie to properly identify that cross-site access is being requested. - **Google Chrome phases out third-party cookies in 2022** – Impacts the ability to set third-party cookies in Chrome. Google proposed to replace tracking cookies with to-be-determined solutions that do not provide 1:1-level tracking but still allow for targeting and block third-party cookies by default in Chrome. Google did not mention any impact on first-party cookies at this time. - **Apple’s Intelligent Tracking Prevention (ITP) for Safari** – Safari continues to block third-party cookies by default. ITP attempts to identify first-party cookies that act as third-party trackers using redirects/bounce tracking, URL decoration, local storage, and other specific practices designed to enable ad targeting. Standard site browsing/serving operations do not commonly use these methods. ITP is unlikely to target a brand’s first-party cookies.