Open Global Persistant UUID

This project is maintained by Polymorph


What is OpenGUID?

OpenGUID (Open Global User ID) is an open source project which allows any publisher or advertiser to retrive a persistent global UUID for a browser, typically attached to a user, with help of simple embeddable javascript. This solution provides persistent UUID with no backend and works cross-domain.

Why do we need OpenGUID?

Unlike iOS and Android devices, where a device can be uniquely and persistantly identified with the help of IDFA and GAID across various apps, web platforms does not provide a persistant way to identify a device uniquely. Without a persistant uuid, it makes it harder for advertisers to correctly identify a user and thereby present and target relevant ads to them effectively. To solve for this, most of the publishers and advertisers use the method of cookies or localstorage to tag a user or device with an unique ID. Generally each entity or partner will add their own scripts to tag the user, which generally adds payload to the webpage. Moreover when each partners are communicating with each other, for example, in an exchange when buyer buys an impression on an exchange, they need to translates the UUID they use to a UUID indetified by the exchange. To do this translation successfully they’ve got into the practise of doing a process called cookie-syncing, which creates a match table of UUIDs between exchange and a buyer. This process is often lossy and ineffective. Worst of all it leads to highly clunky websites and bad user experience.

How does it help me, as a user?

The benefits are two folds - first, have you wondered why some sites, especially news sites are so clunky and slow to load vs the iPhone apps of the same publisher? There are several reasons for it, but one of the important reasons is the amount of javascript ad tags are present on that page. Most of the advertisers demand their javascript tags to be present on the publishers’ webpage so they can drop their own cookies and maintain their own user data. Additionally, some exchange doing the process of cookie-syncing between each partner. With a persistant OpenGUID for a browser we have a genuine shot at cleaning up this ad tags mess and expect a better performance from the various sites. This way advertisers may not have to flood users with bunch of tags. Of course, this is a long-term battle, but the one worth fighting for.

Second, OpenGUID allows users one central control for the ad tracking and experiences they want to opt-in or out of.

How does this help Advertisers?

This essentially replaces the process called “cookie-syncing”. It eliminates any loss of users due to cookie-syncing. It provides more reliable and consistant way to identify a user, so you can maintain various user segments and profiles around a user with more confidence, thereby effectively targeting them. It also works on browsers such as Safari and Firefox, where traditional cookie-syncing fails. So ask your ad-serving provider or SSP to provide you with OpenGUID.

How does this help Publishers?

Generally, the loss of users due to cookie syncing is known to be 10-50% which directly results into the revenue loss, since most of the advertisers don’t even bid without a valid synced uuid of their own. This gives you a clear chance to reclaim that revenue.

Who controls the OpenGUID?

OpenGUID is an open sourced project, under MIT license. The OpenGUID itself for the user is only maintained in the users browser. It does not have any backend servers or storage. So no entity controls it as such and moreover is accessbile to any entity that wants to access it.

The solution is server-less and works cross-domain.

Currently this project is maintained by Polymorph, but any one can choose to participate and our plan is to spin this off as an independant non-for-profit organization.

How do I access OpenGUID?

Place this code anywhere in ‘head’ of your HTML,

<script type="text/javascript" src=""></script>

And then call this anywhere in your html (‘head’ or ‘body’) or JavaScript


Read this documentation for details.

What is my OpenGUID?

This is your OpenGUID,

How can I Opt-out?

Click here to opt-out and click here to opt back in.