What is the fs_uid cookie?
fs_uid is a first- or third-party HTTP cookie set by the FullStory tracking script (fullstory.com), a commercial digital experience analytics tool that records user sessions (session replay), click maps, and behavioral statistics.
The cookie appears as soon as the FullStory tracking script loads on a page, whether the website integrated the code directly or a partner embedded on the page uses FullStory for its own analytics.
What data it stores
fs_uid stores a unique identifier assigned to the visitor, generated by FullStory on the first visit. The value is an alphanumeric string internal to the platform, with no meaning to an outside observer.
The data collected through this identifier (page interactions, mouse movements, clicks, form entries) is sent to FullStory's servers, where it is linked to the visitor's session to enable later playback of the browsing session (session replay).
What it is used for
For FullStory, the cookie allows the same visitor to be recognized across visits and sessions, which underpins the platform's core features: session reconstruction, user segmentation, and behavioral analysis.
For the site owner, fs_uid supports the reports FullStory provides on how visitors interact with the page — where they click, where they abandon a form, where interface errors occur — information used to optimize the user experience.
Does it require consent?
fs_uid falls under the statistics (analytics) category. It is not strictly necessary for the website to function; it serves only FullStory's measurement and behavioral analysis purposes.
- Under Romania's Law 506/2004 (transposing the ePrivacy Directive) and the GDPR, this cookie may only be set after the visitor has given explicit consent.
- Site owners must disclose fs_uid and FullStory's purpose in their cookie policy.
- Since FullStory is a session replay tool that can capture user-entered data, it is advisable to check its configuration to exclude sensitive fields (passwords, card details) from recording.
How to block or delete fs_uid
A visitor can delete or block fs_uid through browser settings (Chrome, Firefox, Safari, Edge — per-site cookie management), or by using tracking-script blocking extensions.
For site owners, the correct approach is preventing the FullStory script from loading at all before consent is given. A CMP like CookieFix automatically blocks such analytics scripts until the visitor grants consent for the statistics category, avoiding premature setting of cookies like fs_uid.
Frequently asked questions
It's not harmful by itself, but it is a tracking cookie used for session replay, meaning it can contribute to capturing detailed visitor interactions on the site. That's why it requires explicit consent.
The typical duration is 1 year from when it's set or last updated, unless the provider specifies otherwise for a given configuration.
No. It is used exclusively for analytics and behavioral statistics, so it falls into the category of cookies requiring prior visitor consent.
You can check your browser's developer tools (Application/Storage tab, Cookies section) or run an automated site scan with a CMP platform that detects active third-party scripts.