I need an experienced ASP.NET / nopCommerce developer to jump straight into an active code-base and wire up Razorpay as the first fully-functional payment option. The work covers the full flow: kicking off the transaction from the storefront, handling Razorpay’s callback, verifying the signature, and persisting the outcome in our order system with rock-solid security in mind. Once Razorpay is live, I also want clean, well-documented REST endpoints that let our upcoming iOS and Android apps read and write all relevant payment and order data. Think create payment session, confirm status, retrieve order history, etc., surfaced in a predictable JSON format that follows nopCommerce conventions. Future milestones will add other UPI gateways—CCAvenue, Pine Labs, and any additional providers we choose—so structuring the code to plug new processors in quickly is important. Key expectations • Razorpay integration completed and test transactions passing in both sandbox and live mode • End-to-end payment flow covered: initiation, callback, signature verification, final order update • Secure coding practices throughout (token handling, HTTPS, callback validation) • REST API layer documented with Swagger or similar for consumption by both iOS and Android teams • Code committed via Git with clear, incremental pull requests so I can review progress easily If you know your way around nopCommerce plugins, understand payment security, and can deliver concise, readable C#, let’s get started right away.