I need a seasoned backend developer to take full ownership of the server-side engine for a new ecommerce platform and stay on for ongoing maintenance as we scale. The scope begins with architecting a clean, well-documented API layer that powers the entire buyer journey—from browsing the catalogue and filling a cart, through checkout, payment, and post-purchase flows such as returns. In parallel, you’ll build out the seller pathway: onboarding, KYC verification, inventory sync, and order management. Key requirements • Robust cart, checkout, and return logic that can handle discounts, promotions, and edge-case calculations without breaking state. • Seamless Razorpay integration (cards, wallets, net-banking—all via Razorpay’s SDK and REST endpoints) with secure webhooks for payment confirmations and refunds. • Modular seller onboarding with KYC document upload, verification status tracking, and the ability to plug in third-party verification services later. • Scalable data models for products, variants, inventory, and orders—optimised for quick search and high-volume writes. • Versioned REST (or GraphQL if you prefer) endpoints, comprehensive unit/integration tests, and clear Swagger/OpenAPI documentation so frontend teams can consume services instantly. • Logging, rate-limiting, and role-based access control baked in from day one to ease future audits and compliance checks. What I’d like to see from you 1. A brief outline of the tech stack you propose (language, framework, DB choice, containerisation/CI). 2. Examples of previous ecommerce or payment-heavy projects—live links or Git repos are ideal. 3. Your estimated timeline to deliver an MVP that covers catalogue, cart, checkout, Razorpay payments, and seller onboarding. Acceptance criteria for each milestone will be defined together, but the MVP will be considered complete when all endpoints return the expected JSON, payments clear end-to-end in Razorpay’s sandbox, and automated tests cover at least 80 % of critical paths. Continuous improvements and long-term maintenance will follow once the core is live.