Hello sir,
I'm an expert Android/Web developer with +8yrs of experience. I have developed many great apps and you can check my profile. Fortunately, I have created an app similar to your app before and it is working great :)
That app was connecting to online web services (not amazon to be honest) like Facebook, Instagram, Google, ... etc.
I can assure you that I will deliver an app beyond your expectations in both technical and quality sides.
Please contact me for more suggestions and to get more details about your app. and let's get this job done.
Thanks and best regards
Ibrahim Radwan
Zend Certified & Android Developer