Razorpay Integration for MERN Store

I have an e-commerce site running on the MERN stack (MongoDB, Express, React, Node). I now need Razorpay fully wired in so customers can complete checkout without leaving the site. Alongside the code-level work, I also need guidance setting up a fresh Razorpay business account—help me from initial signup through to production-ready API keys.

Here is what I expect at the end:

• Backend: Secure Node/Express endpoints that create Razorpay orders, verify payment signatures, and update my existing MongoDB order records.

• Frontend: React components or hooks that trigger the payment popup and handle success / failure callbacks gracefully.

• Account setup: Walk me through activating the account, KYC, and moving from test to live mode.

• Testing & hand-off: Demonstrate successful card, net-banking, and UPI transactions in test mode, then assist in switching to live keys.

Please write clean, well-documented code, bundle any environment variables in a sample .env file, and leave me with clear notes so future developers can maintain the integration. I’m ready to start as soon as you are.