What you have not to do, first. You should not trust chance and look for happiness in the open IT services market. There you can meet really smart freelancers but much more often you can come across banal scammers who know how to convince. Hire a trusted IT outsourcing company such as Alfee - reliable supplier of IT specialists.
The company has a large experience in remote software development. More than 90% of our core staff are the senior and middle software engineers who are specializing in their respective fields (including Stripe development). You can definitely be sure that Alfee specialists will handle all aspects of developing and integrating Stripe custom applications.