@affdata The “easiest” solution is to stick with what you know. You’re asking about Spark, a third-party template, and Vapor. That’s a steep learning curve.
I’d also question the use of a Vue SPA. Will your application actually benefit from an SPA over a “traditional” server-rendered application?
Spark is a fine starting point for SaaS applications as that’s what it was built for. It has it’s own Vue-based control panel for managing teams and subscriptions, but you’ll need to build the actual logic and screens for your application. It’s impossible to tell how well a third-party template will slot into this.
Personally, I wouldn’t use Passport and Cashier if all I was going to do is re-build what Spark already does.
I have mainly decided to go with Vue SPA because I also want to learn about the whole concept in the process of making this project. SPA applications are something that attracted me for a long time but I didn't have time to dig in.
What are the parameters I should look on when trying to understand whether my project is going to benefit from a SPA?