Full Stack Developer for Feature Enhancement

I'm seeking a skilled Full Stack Developer proficient in Node.js, React.js, and MongoDB. The project involves setting up the project, integrating a payment gateway (any), and fixing existing errors.

Key Tasks:
- Payment gateway integration (e.g., PayPal, Stripe, Square)
- Fix performance issues, functionality bugs, and UI/UX issues based on existing designs

Ideal Skills and Experience:
- Strong background in Node.js, React.js, and MongoDB
- Experience with payment gateway integration
- Ability to troubleshoot and resolve performance issues and bugs
- Familiarity with UI/UX principles and existing design implementation

Looking for someone who can deliver quality work efficiently. Please share your relevant experience and approach.