Hiring a mobile app developer who will provide you a quality app can be accomplished with a little bit of research and a project discussion with the company before entering into an official contract. Look up or ask about their previous projects, and see if they have worked on a project the size you will need; inquire about their follow-up quality assurance and maintenance, and determine if you will need 24/7 support once your app goes live. Check reviews, ask for testimonials, and be clear about what you need.