Hi @trevin-bc 

The “First Seen” property is just UI based on the user profile level and can’t be queried as a custom user property.

If you have access , then Computations or derived properties feature might help in creating this property on the fly.

But I feel it’s a better option to instrument this and set it as a custom user property on the user’s very first event if possible.

I’m so shocked this isn’t queryable given amplitude knows this data already.  In our identify calls, is the right solution to set a custom “First Seen” property using `setOnce`?

How does this work in this case:

1. User anonymously visits our site on device1, tthey are auto assigned by amplitude a userid=1
2. User anonymously visits our site on device2, they are auto assigned by amplitude a userid=2
3. On device2, they sign up and create account and their userID is set to our internal user id of ABC.
4. on device1, they sign in with that same account, so now that device is then user id ABC as well.
5. Now the auto generated IDs are auto reconcicled by amplituded and merged

But if I set the custom First Seen property in both step 1 and 2, what happens on merging?  Each device has a first seen that is different and we’d want it to always be the earliest of the 2

Hey @Saish Redkar !

I have one more question regarding this topic. We want to track the totals for one event performed on the first 7 seven days since signup. We have been told to instrument the signup date as a user property and then create a custom user property. Is that correct, and if yes, could you share an example of the custom property´s syntax?

Thanks!