Journey start only after receiving 2 events from 2 different streaming data sources

Question

Hi all,

I have a requirement where I want to start the journey after the user has performed a transaction and an additional event from Pega has been received.
The flow of events is such that a transaction will be made by the user at a store, that event will be received via the transaction events dataset (experience event). When the transaction event will occur, there will be another event received soon after it (sometimes it may be received earlier in AEP) containing some offer details.

I want to utilise context data from both event calls and use the context data within the message/email.

E.g. user went to the store and made a purchase of $X in the store ABC. This transaction is sent to AEP in real time.
Because of user's this activity, Pega created an offer and sent it to AEP in real time as well.
The catch is sometimes the Pega offer can come earlier and sometimes the transaction event can come earlier.

I want the user to only enter the journey when both the events have been received in AEP.

Then, I want to use the context data from both the events in the message, like this:

Hey $firstName,

Because you made a purchase of $X on store ABC, you are eligible for the offer123.

What approach should I follow to achieve this use case?
Should I start the journey on audience qualification? I believe I won't be able to use the context data in the message in that case.

Thanks

Mohan_Dugganab · Accepted Answer

You can use one of the events to start the journey, wait for x minutes / hours before the other event arrives and then access the relevant attributes from the second event using collection management functions https://experienceleague.adobe.com/en/docs/journey-optimizer/using/orchestrate-journeys/building-advanced-conditions-journeys/syntax/collection-management-functions to write the relevant event attributes back to a dataset which can be used as a trigger for the actual journey.