How do I identify a user on another website?

Started by richerd, Mar 13, 2023, 02:53 AM

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richerdTopic starter

For instance, there are two websites - and When a user visits, we need to find a way to remember this visit so that when the user goes to, we can accurately identify them as the same user. Basically, we need to leave some kind of identifier during the visit to (where could we put it?)

On the first domain, JavaScript can be used, but on the second site, the user's identification should happen at the PHP level immediately.

Without considering the IP address, it is initially unknown what the address of would be (when entering Both sites can be hosted on the same hosting provider.

Is this feasible?


I personally don't endorse fingerprinting, so I'll present my own approach on how it can be done.

Here's an alternative solution: On, you can implement a JavaScript code (possibly using jQuery) that sends an XMLHttpRequest to On, there should be a corresponding code to receive and process the user's request (preferably in JSON or a similar format). The key aspect is to ensure that the client-side request is not blocked and can synchronize between and

As a result, will receive the user's request, and will also receive and store this request along with Both sites can share a common database that is synchronized, and this database can be hosted on either site.

It's important to mention that synchronizing and sharing data between multiple websites requires careful consideration of security and privacy implications. Additionally, ensuring that the implementation adheres to legal regulations and best practices is crucial.


To achieve this, you can store the fingerprint data in the database of the first site. Then, on the second site, you can establish remote access to the database of the first site.

Creating a centralized database that can be accessed remotely from different sites can provide a way to maintain continuity and synchronize user information between multiple domains.

It is worth noting that ensuring the security and privacy of the stored data is of utmost importance. Implementing proper authentication measures and encryption protocols is crucial when dealing with sensitive user information across different sites.