iPhone Gallery application + connecting 3 API's

We are looking to have developed a simple gallery & print service app. The app pulls images from a source ([login to view URL]), sends a user selected image to a print on demand service ([login to view URL]) and takes payment via Stripe.com. All three services have extensive APIs and great documentation. We have created the complete workflow for the App and require you to code (in your choice of language) and connect the three API’s together. Please look at attached PDF for full project scope. Services: Preferable Google Firebase but we have a dedicated server available. APIs: Unsplash API [login to view URL] Gooten API [login to view URL] [login to view URL] Stripe [login to view URL] Communication: We will be using a Slack channel Payment: 50% at working prototype. 50% after launch on app store Working Files: Sketch files PDFs