> For the complete documentation index, see [llms.txt](https://docs.mediarithmics.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.mediarithmics.io/audience-and-activation/build-your-audiences/segment-reference/segment-types/edge-segment.md).

# Edge segment

The segment type evaluated by the user's own browser, in near real time, rather than by mediarithmics servers.

## What it is

**Edge** is a segmentation feature that runs **client-side**, inside the user's browser, instead of relying on server-side segmentation. Each user's browser evaluates whether that user belongs to a segment, based on the interactions it has recorded on your site - which makes membership close to real time.

Edge is not available by default. Contact your mediarithmics Account manager to have it activated on your channels. The setup itself - snippet version, schema flags, ad server wiring - is documented in the **Setup & Monitor** section, under *Edge*. This page covers the segment as an audience object.

## Edge versus server-side

<table data-search="false"><thead><tr><th width="150"></th><th>Edge</th><th>Server-side</th></tr></thead><tbody><tr><td><strong>Who evaluates</strong></td><td>The end user's browser</td><td>mediarithmics servers</td></tr><tr><td><strong>When</strong></td><td>Near real time, as the user browses</td><td>On the segment's evaluation period, usually overnight</td></tr><tr><td><strong>What it can see</strong></td><td>The visit timeline held in the browser's local storage</td><td>Any criteria stored in the datamart</td></tr><tr><td><strong>Who is in it</strong></td><td>Only users who browsed your site with Edge active</td><td>Every user matching the query</td></tr></tbody></table>

{% hint style="info" %}
**The same audience, both ways.** A sales house wants to activate people who like high-tech products. With **Edge**, the segment is defined on user activity and a visitor enters it the moment their browsing matches the criteria, with activation triggered on Google Ad Manager on each subsequent page. With a **server-side** segment, the same audience is defined on anything in the datamart, computed overnight, and activated once a day.
{% endhint %}

For high-volume, precision-driven segmentation that needs cross-site behaviour and broader aggregation, server-side segmentation remains the recommended approach. Edge is the right choice for instant on-site personalisation and targeting.

## How a user enters one

{% stepper %}
{% step %}

### The tag records the visit

The user visits your site, the mediarithmics tag runs, and the user's **visit timeline** is stored in local storage.
{% endstep %}

{% step %}

### The browser fetches the definitions

The browser downloads all Edge segment definitions from mediarithmics - JavaScript-based segment queries.
{% endstep %}

{% step %}

### The browser evaluates them

The definitions are evaluated against the visit timeline, in the browser.
{% endstep %}

{% step %}

### Membership is stored and reported

The segments the user belongs to are written to local storage, and synchronised back to mediarithmics for analytics.
{% endstep %}

{% step %}

### Activation fires

Edge segments are activated on Google automatically, as key-value targeting through Google Publisher Tag.
{% endstep %}
{% endstepper %}

{% hint style="info" %}
During setup you can agree a custom targeting key - a `namespace` - with your Account manager. It is automatically prefixed with `mics_`: a namespace of `dogfooding` produces the Google Ad Manager targeting key `mics_dogfooding`.
{% endhint %}

## What is stored in the browser, and for how long

|                       | Visit timeline                                                                        | Segments                                   |
| --------------------- | ------------------------------------------------------------------------------------- | ------------------------------------------ |
| **Local storage key** | `<namespace>_mics_up`                                                                 | `mics_sgmts`                               |
| **Limit**             | Up to 200 events per domain and user. Beyond 200, each new event replaces the oldest. | No limit on the number of segments stored. |
| **Expiry**            | None. No automatic cleaning.                                                          | None. No automatic cleaning.               |

## Three consequences to plan around

* **Statistics lag.** Segment membership is synchronised for analytics, but segment statistics updates can take up to 24 hours. The audience is real time; the number you read is not.
* **Users do not always exit.** If a criterion is time-sensitive - "visited a product page in the last 10 days" - and the user never returns to the site, nothing re-evaluates the definition, so the user does not leave the segment even though they no longer match.
* **Consent still applies.** Edge follows the same consent management requirements as the rest of the platform. See **Setup & Monitor**, under `Manage consent & Processing activities`. Note that Edge segments are among the types that cannot carry a processing activity - see [Enforce compliance on your audience](/audience-and-activation/build-your-audiences/enforce-compliance-on-your-audience.md).

## Activating beyond Google

Google Ad Manager is wired in automatically. For other platforms, add a server-side [feed](/audience-and-activation/activate-your-audiences/set-up-a-destination/feed.md) on the Edge segment, exactly as you would on any other segment.

## Related pages

<table data-view="cards" data-search="false"><thead><tr><th></th><th></th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td><strong>Build your audience from live user activity</strong></td><td>Choosing between Edge, automations and campaign segments.</td><td><a href="/audience-and-activation/build-your-audiences/target-your-audience-based-on-criteria/build-your-audience-from-live-user-activity.md">Build your audience from live user activity</a></td></tr><tr><td><strong>Use contextual targeting in segments</strong></td><td>Contextual criteria in an Edge segment need no event-rule option.</td><td><a href="/audience-and-activation/target-contextually/use-contextual-targeting-in-segments.md">Use contextual targeting in segments</a></td></tr></tbody></table>


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