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Migrating From a CST to an eCST

The Enhanced Client-Side Tag (eCST) is an upgrade over the standard Client-Side Tag (CST) in that the eCST allows for better enablement of your cross-device retargeting or measurement efforts. It does this by enabling the collection of additional device identifiers, beyond just LiveRamp cookies, and allows for the collection of ATS-created identity envelopes that contain RampIDs.


To migrate from a CST to an eCST, perform the following steps:

  1. Decide which environments you want to fire the eCST in. For example, if you want to collect MAIDs, then you must have access to an in-app environment. Deciding which environments you are able to fire the eCST in will help inform you which devices you can ultimately capture for use in the eCST.


    • You cannot pass MAIDs through a mobile web browser as the browser will not have access to the user’s MAID.

    • Generally the use of macros will help you populate any additional device identifiers outside of LiveRamp cookies that you’d like to collect. For example, if you’re using the eCST to capture MAIDs on an in-app measurement workflow, you’ll need to confirm with your DSP their MAID macro and ensure it is passing the MAID to the eCST correctly.

  2. Talk with your LiveRamp representative about your interest in upgrading to eCST and work with them to procure an eCST contract.


    If you’d like to collect identity envelopes through your various owned and operated properties, talk with your LiveRamp representative about your interest in deploying ATS and work with them to procure an ATS contract and complete a privacy policy review.

  3. Once eCST paperwork has been squared away, update the request URL of your CST to the eCST request URL. Below is an example of how you might upgrade your existing CST URL request to the URL request for an eCST that allows you to send Identity Envelopes along with pdata.

    Existing CST URL Request

    Updated URL Request for eCST;it=19&amp;iv=<ENVELOPE VALUE>&pdata=key1%3Dvalue1%2Ckey2%3Dvalue2


    You must use the new eCST request URL in order for it to process your identifiers and key/value pairs properly.

    As seen in the example, you can use the same tag ID you had for your CST. Your LiveRamp representative will make the necessary configuration changes on LiveRamp’s backend to ensure the tag ID has been upgraded.


    You do not necessarily have to use the same tag ID, however it is an option if you’d like. Let your LiveRamp representative know if you plan on using the same tag ID for your eCST implementation.

    Each additional device type you collect will add another audience or RampID log file, depending on your use case.

  4. Check out your new audiences or RampID log files. After testing begins, you should have access to your new audiences in Connect or your newly-created RampID log files. Check that these have all been generated properly.