We have an App with Mobile SDK installed. After registration a Contact is created (with an auto-generated Contact Key, since we don't specify one).

We have a input field on the app allowing the user (which is known by a device ID at this stage) allowing our users to add their Email Address.

We use an Attribute added on Mobile Push Attribute Group to send the Email back to MC, fed with the input field above.

How do we transfer this Email Address in Email Studio so that it can be used in a cross channel send (Push + Email) in JB ?

Many thanks in advance for any insight !


  • You should open a support case. StackOverflow is used for programming questions.
    – Bill Mote
    Commented Jul 25, 2022 at 12:36
  • 1
    Done, thanks @BillMote ! Commented Jul 25, 2022 at 13:57

2 Answers 2


If you populate a DE with the new app registrations, just send an email from JB using your email field from the App (not from Contact Builder) in Journey settings, and you user will be added as subscriber in Email Studio without further work.

  • 2
    Thanks, that makes sens. Commented Jul 28, 2022 at 13:03
  • 2
    Mind Email Studio Subscriber Key which cannot be simply edited. Commented Jul 28, 2022 at 13:26

Yes, no need to explicitly add a subscriber, just send to him/her. Keep in mind though that you won't be able to change you Contact Key in Email Studio later on. If you change the Contact Key in Mobile Push from SDK, and send an email again, a send subscriber will be created in Email Studio.

  • 2
    Yes, Subscriber Key Migration can be long and expensive. Commented Jul 28, 2022 at 13:27

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