All fields with the name uuid are generated by our marketplace vendor and will not correspond to anything in the Q2 platform.

sso_user_id is a guid that we generate in the marketplace to link an online banking user to an SSO user within our vendor's system, as well as the customer key for the FI environment that the event originated from (deliniated with a ':' ). The first piece will likely not be useful to you as a partner developer. The second can be useful to populate HQ credentials from Vault at request time. However, the q2-marketplace library will do this for you in the background, so this shouldn't be necessary unless you're overriding that behavior.

user_id is the integer ID that matches up with the user ID in the FI database and can be used to look up user information.

Yes, both subscription IDs would match in a real environment. This is a mistake in the sample payload.

We are aware that this event payload in its current form is redundant and hard to parse. We are working on making the developer experience around subscriptions better. In the meantime, I would recommend ignoring the nested subscription_event object if possible, and focusing on the other top level elements to find useful data.