Real-Time Product Price Comparison System

Description:
I want to build a real-time product price comparison and tracking system.

A customer will paste a product URL (e.g., a MacBook from Amazon).
The system will automatically search the same product across multiple e-commerce platforms (Amazon, Flipkart, Croma, Ajio, Reliance Digital, etc.).
It will then compare prices and show the customer the best deal.
The purchase should redirect through my affiliate links so I earn commission.
I tried web scraping, but my IP got blocked after ~20 requests. So I now want to build this using official APIs (Amazon, Flipkart, etc.) wherever possible. Scraping should only be a fallback if no API is available.
The system should be robust, scalable for 1000+ users, and include a subscription plan (monthly/annual) for customers.

Core Requirements:
Fetch product details (price, stock availability, discounts) from multiple e-commerce sites.
Handle high concurrency (1000+ active users).
Subscription & payment gateway (Stripe / Razorpay).
Affiliate program integration (Amazon, Flipkart, etc.).
Documentation on adding new platforms in the future.
Deployment support (AWS/Hostinger/VPS).

Example Flow:
User pastes a MacBook URL from Amazon.
System searches the same product on Flipkart, Croma, Ajio, and Reliance Digital.
Shows all available prices.
Redirects user via affiliate link for purchase.

Skills Required:
API Integration (Amazon, Flipkart, etc.)
Web Scraping (fallback if no API)
Node.js / Express.js OR any fast backend language (Python, Go, Java, etc.)
React.js (Frontend)
Payment Gateway (Stripe / Razorpay)
Affiliate Marketing & API knowledge
Technology Preference:
Any language is fine (Node.js, Python, Go, Java), but solution must be fast, scalable, and reliable.