shashankpk31/razorpay_simulator — reverse-engineered prompt

Build me a local Razorpay payment gateway simulator for testing payment flows without using a real Razorpay account.

It should be a Java Spring Boot app that runs on port 9000 and lets me create test orders, open a Razorpay like checkout page for an order, try card, UPI, net banking, or wallet payments, and simulate both successful and failed payments. Include test cards for success, declined card, expired card, invalid CVV, and Mastercard success.

I also want an admin dashboard where I can see order counts, payments, revenue, transaction history, webhook settings, and test card scenarios. The API should mimic Razorpay enough for local development, including creating orders, getting orders, capturing payments, basic auth with test keys, webhook callbacks, and signature verification.

Use an H2 database so it works locally without setup, and include clear run instructions with Maven and Java 17. This is only for testing and demos, not real payments.