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the logic of ECID generation


Level 1



I am very curious about the generation logic of ECID. According to the official document: In the context of Identity Service, ECID is used as the primary ID for devices and as a base node for identity graphs. I found that there are multiple ecid for the same cookie, so what factors are involved in judging the uniqueness of the ecid? If possible, please provide examples.




4 Replies


Community Advisor

Can you provide more information about what you mean by "multiple ecid for the same cookie"?


In the Cookie, there is only one ECID, but there are some supplemental information that is part of the cookie.. I don't know if these values are all fully documented, but I am thinking you are trying to understand all the data that is part of the cookie?


Level 1

so your mean only one ECID for one cookie correct? The situation I found: e.g. cookie (id:451-VAW-614&, I found two corresponding ecids in the database. Is it unnormal? That's why I want to figure out what factors are involved in judging the uniqueness of the ECID.

If I can understand the factor, it can better facilitate my follow-up work.


Community Advisor

Ok, I think I am going to need some more information... what is cookie (id:451-VAW-614&


Is that a cookie that your system is setting?


Depending on your implementation, users could get an initial ECID on your website, and a second one on your apps... if you install the extension to pass the App's ECID to the website (when opening the website from the app), or appending the ECID from one site to another site in a multi-site organization... a user can be moved from one ECID to another in an effort to stitch them together. While Adobe does it's best to properly identify users and set the same ECID to a user, the way in which people use and interact with sites and browsers, and as more and more privacy concerns are raised around cookie usage, passing ECIDs between different instances are used to help improve tracking, but this can result in users having their ECIDs updated/changed... which might be what you are seeing.


Here are some resources I found around ECID:


Maybe this will help you out.


Community Advisor

There are a few reasons why the same logged in user would have more than one ECID. Jennifer has described one situation: web vs app.

Some other reasons:

  • The user uses private browser windows. Such windows always delete their cookies and cache when the user closes them.
  • The user uses more than one browser. Cookies are saved to browsers, so there could really be one cookie in each browser for the same user on the same device.
  • The user uses more than one device. Again, cookies are saved to browsers, and browsers run on devices, so there could really be one cookie in each browser per device for the same user.
  • The user deletes cookies. Yes, it happens. Why not?

Why you can still get the same value for your cookie (id:451-VAW-614& is most likely because your system can identify the user uniquely (most likely through a login), and so the same value always gets saved in that particular cookie despite the above reasons.