What is the cf_use_ob cookie?
cf_use_ob is an HTTP cookie set by Cloudflare, the content delivery network (CDN) and security provider used by a very large number of websites. It is not set directly by the website owner, but by the Cloudflare infrastructure sitting in front of the site.
It typically appears on a visitor's first interaction with a site protected by Cloudflare, as part of the internal mechanisms the network uses to manage request delivery and routing. Its exact presence can vary depending on each site's specific Cloudflare configuration.
What data it stores
cf_use_ob stores an internal technical value, generated and interpreted by Cloudflare's systems, used to manage connection routing behavior at the infrastructure level. The exact value format is not documented in detail publicly by Cloudflare.
The data is sent to Cloudflare's own servers, not to the site owner or unrelated third parties. The cookie has a typical lifespan of about 1 minute, indicating a strictly operational, very short-lived role.
What it is used for
The purpose of this cookie relates to the correct and efficient operation of the Cloudflare infrastructure that mediates traffic between the visitor and the site's origin server. It helps maintain connection stability and optimize how requests are handled across the network.
For the site owner, this type of cookie does not serve marketing, analytics, or profiling purposes — it supports the technical functioning of the Cloudflare services the site relies on (CDN, DDoS protection, performance optimization).
Does it require consent?
In CookieFix's classification, cf_use_ob falls under the necessary (strictly necessary) category. Under EU data protection authority guidance and the ePrivacy interpretation (transposed in Romania via Law 506/2004), cookies strictly necessary for the technical functioning of a service explicitly requested by the user do not require prior consent.
- The site owner does not need to obtain consent for this cookie.
- It should still be listed, along with its purpose and provider (Cloudflare), in the site's cookie policy to meet GDPR transparency obligations.
How to block or delete cf_use_ob
A visitor can delete or block cf_use_ob through browser settings (Chrome, Firefox, Edge, Safari), via per-site cookie management, or by using private browsing mode. Blocking it could, in theory, affect how the Cloudflare network optimizes content delivery for that site.
Because it is classified as strictly necessary, a CMP such as CookieFix does not need to block it automatically before consent, unlike statistics or marketing scripts — those are held back until the visitor gives consent.
Frequently asked questions
It's a technical cookie set by Cloudflare, used internally to manage routing and content delivery infrastructure on sites running behind the Cloudflare network.
No, it's an operational cookie tied to how the Cloudflare network functions, with a very short lifespan (around 1 minute), and it is not used for marketing profiling.
No, since it's classified as strictly necessary, visitor consent isn't required, but it should be disclosed in the cookie policy.
You can remove it through your browser's privacy/cookie settings, the same way you would delete any other site cookie.