---
title: "How to deduplicate with markers"
slug: "how-to-deduplicate-with-markers"
description: "Control tag frequency and avoid double-counting conversions with deduplication conditions and markers stored in cookies for precise tracking."
updated: 2026-06-24T11:02:27Z
published: 2026-06-24T11:02:27Z
canonical: "docs.supermetrics.com/how-to-deduplicate-with-markers"
---

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

# How to deduplicate with markers

Deduplication lets you control how often a tag runs for the same visitor, so you don't double-count conversions or run a tag more than you mean to. You set a marker when something happens, then add a deduplication condition so a tag runs only when the right marker is present or absent.

- A **marker** is a client-side flag stored in a cookie in the visitor's browser. Markers are time-based and organized into groups. Each marker has a group, a name, and an expiry time. The expiry is checked each time the visitor loads a page, and an expired marker is removed.
- A **deduplication condition** checks whether the visitor has a given marker before the tag runs. You can check for more than one marker at once.

## Before you begin

You can only add a deduplication condition to an existing tag to make the tag run based on a marker. To create a tag first, see [How to create and manage tags](/v1/docs/how-to-create-and-manage-tags). For how conditions work in general, see [Tag targeting rules](/v1/docs/how-to-use-tag-targeting-rules).

## Instructions

1. In Data Activation, navigate to **Tags** and select **Pages**.
2. Open the tag you want to deduplicate.
3. Click the pencil icon to configure rules.
4. Select the **Deduplication** rule.
5. Enter the marker group and marker name to check.
6. Save the rule.
7. Publish your changes to apply the rule on your site.

## 

## More resources

- [How to use tag targeting rules](/v1/docs/how-to-use-tag-targeting-rules)
- [How to create and manage tags](/v1/docs/how-to-create-and-manage-tags)