You'll want to be more specific, WHAT do you need to integrate exactly, What is the goal?
Are you trying to dropship? you need fulfillment? you need framing options? personalization?
Thanks for reaching out.
I took a deep dive into our App Store to see which third-party applications have the feature you are looking for. I created a list of recommendations for you to take a look through, feel more than welcome to select the links to be taken to the application page:
With that being said, each page will have a full description of the features and examples of the third-party application.
Let me know what you think, looking forward to your response.