Web App Feature Implementation

I have a live web application that is ready for the next set of capabilities, and I want to move quickly. The immediate goal is to add three concrete features so the product can scale to paying, socially engaged users. Deliverables • User authentication – secure sign-up, log-in, password reset and session handling, ready for production. • Payment integration – connect a mainstream gateway such as Stripe or PayPal, handle one-off and recurring charges, return clear success/failure callbacks. • Social media sharing – lightweight share flows for the major networks so users can broadcast content directly from the app. I am not focused on bug-fixing or performance tuning right now, but if you spot an optimisation or edge-case while you work, I’ll happily take your recommendation. Clean, well-commented code, concise commit history and a short setup guide are required for acceptance. If parts of the stack need clarification, tell me in your proposal and I’ll share the current tech details. Let me know your preferred frameworks or libraries for auth, payments and social sharing, rough timeline, and any similar work you can point to.