> ## Documentation Index
> Fetch the complete documentation index at: https://docs.kameleoon.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Predefined tags

> Apply predefined tags like TECHNICAL, DELAYED, LIVE-UPDATE, HOLDOUT, and MUTUALLY EXCLUSIVE GROUP to modify how Kameleoon runs your experiments.

There are predefined tags that you can use with your experiments to change the default behavior of Kameleoon:

* **TECHNICAL**:\
  When you add a `TECHNICAL` tag to an experiment, Kameleoon will display the variation of the experiment, but no data will be collected or sent to an analytics platform until [consent](../../../project-management/consent-management-policy#consent-policy) has been given.\
  This tag is typically used for experiments or personalization campaigns that display the same variant to all users.

* **DELAYED**:\
  Adding the `DELAYED` tag to an experiment allows you to delay non-essential experiments until after the first page load. Experiments with this tag are intelligently managed:\
  Kameleoon doesn't download the configuration until an idle time of at least 10 seconds after the initial page load **or** until the visitor is targeted and allocated with a variant that is not the control variant.

* **LIVE-UPDATE**:\
  By default, Kameleoon downloads active experiments and includes them in the application file (`kameleoon.js`).\
  The browser stores and caches this file for 90 minutes. If you stop or modify an experiment, targeted visitors returning to a page with active experiments within the 90-minute caching period may still see the experiment due to the cached version.\
  To make more frequent updates without being impacted by browser caching, the `LIVE-UPDATE` tag refreshes any experiment within **one minute**.\
  This is particularly useful for campaigns that require regular updates.

* **HOLDOUT**:\
  Create a control group that remains unaffected by any active campaigns. This allows you to establish a reliable baseline to measure the aggregate impact of all changes against a group that experiences no modifications.\
  Set up an experiment in Kameleoon and tag it with the `HOLDOUT` label.\
  [More about this tag](./create-reliable-baselines-with-holdouts)

* **MUTUALLY EXCLUSIVE GROUP**:\
  Group campaigns so that each visitor sees only one campaign per group, reducing overlap and improving test clarity.\
  Follow the naming convention `ME-GROUP-{GROUP NAME}` to tag each campaign in the group, such as `ME-GROUP-A`.\
  This naming signals Kameleoon to treat the campaigns within each group as mutually exclusive.\
  [More about this tag](./prevent-overlapping-campaigns-with-mutually-exclusive-groups)