When a visitor enters a site running the Frosmo Platform, the Frosmo JavaScript library loads in the visitor's browser and starts tracking the visitor's activities on the site. For tracking purposes, the platform automatically sets the following indicators to each visitor:

Local Frosmo ID

This ID uniquely identifies the visitor inside a single site. The ID allows the platform to track the visitor's interactions on the site and retrieve data specific to them from the Frosmo back end.

The platform generates the ID from the user agent (UA) string of the visitor's browser and the timestamp of their entry to the site. The ID does not contain any personal data that can be used to identify the visitor's person.

The platform stores the ID in the visitor's browser, either in local storage or in a first-party cookie. If the browser cache for the site is cleared, either manually by the visitor or automatically by the browser, the ID is deleted from the browser. The visitor's next interaction on the site with the same browser registers them as a new visitor with a new ID.

Global Frosmo ID

This ID uniquely identifies the visitor across all sites of a company. The ID does not contain any personal data that can be used to identify the visitor's person. The platform stores the ID in the visitor's browser in a third-party cookie.


The platform randomly places every new visitor in one of ten deciles. The visitor stays in the same decile until they clear their browser cache. The deciles are built-in visitor segments to which you can target modifications. By default, modifications display to all ten deciles, but you can set individual modifications to target only selected deciles. The visitor's decile placement applies across all modifications on a site.

You can use deciles on their own or in combination with segments and affinity groups to refine the target audiences of your modifications. For example: You can target just part of a segment by assigning a modification to the segment and setting the modification to target only selected deciles. A visitor will see the modification only if they are in the segment and in one of the selected deciles.

Comparison group

The comparison group consists of visitors who see the original content of a web page instead of modifications. The platform automatically places 10% of all visitors in the comparison group. An individual visitor always either belongs or does not belong to the comparison group.

For visitors in the comparison group to see the original content instead of a modification, the modification must have its comparison group variation enabled. If enabled, visitors in the comparison group do not see the modification, while visitors not in the comparison group see the modification normally. If the comparison group variation is disabled, all visitors see the modification, including those in the comparison group. Once a visitor enters the comparison group, that visitor will not see any modifications on the site that have the comparison group variation enabled.

The comparison group allows you to monitor modification performance as compared to your original content.

If you want to use the comparison group on your site, enable it for all modifications. This ensures that the modification statistics for your site remain internally consistent and mutually comparable.