Skip to content Cookies uses first-party cookies to power a number of features. This guide will describe our cookies, how long cookies last, their benefits, and alternative implementations.

A screenshot of Chrome Developer Tools showing three cookies. cookies as seen in Chrome Dev Tools > Application > Storage > Cookies > [tracked domain name]


The following table lists every assignment to document.cookie that our JS SDK can make. We will not always write or read these cookies on every Parsely-tracked pageload.

All of these cookies are set on the domain of the integrating page, so they are considered first-party cookies. The tracking logic used by the SDK does not set any third-party cookies.

Depending on browser compatibility and user-settable configurations, all of these pieces of data may be stored either in document.cookie or in window.localStorage. Regardless of the storage medium, they are functionally identical.

CookiePurposeTime To Live (TTL)
testused to discover cookie support, value undefinednone
_parsely_visitorJSON document uniquely identifying a browser and counting its sessions13 months
_parsely_tpa_blockedJSON document storing a flag indicating whether is not accessible by the tracker12 hours
_parsely_slot_clickexplicitly cleared on some tracker loads, JSON document storing positional information about a clicked internal linknone
_parsely_sessionJSON document storing information identifying a browsing session according to Parsely’s proprietary definition30 minutes


Several of our features benefit from these cookies. That includes distinguishing between new and returning visitors, informing the API Recommendations endpoints, Overlay slots, and providing a chain of content attribution for your conversions.

Likewise, you can benefit from setting your own cookies to enable audience segmentation.

Alternatives can track metrics from your primary domain and its subdomains without additional configuration. But if you may configure our tracker so that each subdomain has its own first-party cookie pool. To set that up, follow these instructions.

If you want to use LocalStorage instead of Cookies, then we have guidance for that as well here.

You might need to delete cookies for troubleshooting purposes. To do so, follow these instructions.

If you’re reading about Cookies, then you may be interested in’s Privacy Policy and the cookie policy of Automattic, our parent company.

Please contact Support if you have any questions about Cookies.

Last updated: December 11, 2023