Here are the steps to offering Upsell via the UltraCart API.
Use the built-in upsell gauntlet. Don't use the API. If you're determined to use the API, please read on...
Reasons to use the built-in Upsell
- It's easy to use and allows for complex upsell paths.
- It removes tremendous complexity from the checkout
- It has a great dashboard and metric tracking.
Objections to using the built-in Upsell
Objection: "We want to keep control of the checkout on our site."
Response: Why? You can hand off to UltraCart and then immediately redirect on the receipt page if needed. It's done all the time.
Objection: "We'll have to style up the upsell and receipt pages to match our site"
Response: Yes, but the time spent copying and pasting css code is nothing compared to the time required to implement an api based upsell.
Objection: "I only know PHP. I don't know Velocity."
Response: You probably won't even use the template language. Very few implementations have need of Velocity. But if you do, it's easy to learn and UltraCart Support is there to help you out.