Hi, we need to send in-store data to our Marketo account (via API) and then use that data to trigger customer journeys and reference specific data in the email template. More specifically, we want to trigger a customer journey when a person opts for a digital receipt in a store. We then want to send them a follow-up Product Rec type email from Marketo based on their in-store purchases "x" number of days after.
What would be the best way to do that? Should we set up a Custom Activity to first initiate the e-receipt trigger to start a customer journey? Then pass the transaction data values (e.g., SKUs, Colors etc.) we need for the emails via Custom Objects, so that we can refer to them via Tokens? Or is there a better/easier way to accomplish this?
No need for Custom Activities here. You only need a Custom Object.
The only advantage of CAs are that they are non-repudiatable (that is, read-only additions to the Activity Log -- until they age out) and they're easier to scan for in the ActLog. In all other ways, COs are superior, including the ability to be included in emails via Velocity tokens, as you mention.
With COs, just be careful of API limits. A high volume of small-ticket purchases wouldn't be feasible for either COs or CAs.