Note
Optimizely Forms is only supported by MVC-based websites and HTML5-compliant browsers.
## Cookie usage in Optimizely Forms
Optimizely Forms uses the following cookies:
| Cookie Name | Purpose |
| **.EPiForm\_VisitorIdentifier** | Functionality-related. Identifies the form submission to the site when a visitor submits data to via an Optimizely form. Stores a GUID which is the visitor identifier. Persistent (90 days from creation). |
| **.EPiForm\_BID** | Functionality-related. Identifies the form submission made to the site when a visitor submits data via an Optimizely form. Stores a GUID as the browser ID. Persistent (90 days from creation). |
| **EPiForm\_{FormGuid}:{Username}** | Functionality-related. Stores partial form submissions so that a visitor can continue with a form submission upon return. One cookie is created for each form and each logged in visitor. Stores the current submission status of the form (formGuid, submissionID, and if submission is finalized or not). Persistent (90 days from creation). |
Note
The following are **internal cookies**Â (implemented by below service classes) and should not be touched. If you really need to, change the class to your implementation.
**EPiServer.Forms.Core.Internal.ProgressiveSubmitInfoService**
**EPiServer.Forms.Core.Internal.VisitorIdentify.DefaultVisitorIdentifyProvider**
You can set up a time to expire these cookies by changing the value of `visitorSubmitTimeout` in _Forms.config_. The default is 90 days.
## Protect visitors' privacy
According to EU directives, website owners are responsible for informing visitors about cookies used on the site. See [Protecting your visitors’ privacy according to EU directive on cookies](🔗).