Trade Link Network
A UK-focused leads marketplace platform that connects homeowners looking for trade services with local professionals such as plumbers, electricians, roofers, and other tradepersons.
Project Overview
A UK-focused leads marketplace platform that connects homeowners looking for trade services with local professionals (plumbers, electricians, roofers, etc.).
Architecture & Engineering Contributions
Designed and built the entire modular feature-based backend using Node.js, Express, and TypeScript.
Implemented postcode-based geographic matching and working radius limit logic.
Integrated Stripe payments and webhooks with dynamic, locked lead pricing calculations.
Configured SMS and email verification flows using Twilio and Nodemailer.
Created a comprehensive admin dashboard to manage users, pricing, reviews, and transactions.
Key Architectural Challenges & Solutions
Calculating geographic radius limits and postcode matching in real-time without hurting database query performance.
Utilized MongoDB 2dsphere geospatial indexes and $nearSphere queries, combined with caching UK postcode coordinates in Redis.
Preventing race conditions where multiple professionals try to purchase the same lead concurrently.
Implemented pessimistic locks using Redis-based lock tokens, ensuring that a lead's purchase limit of 3 is strictly enforced under high load.
Handling webhook payment failures or user disconnects during Stripe checkout.
Created an idempotent Stripe webhook processing system with transactional rollbacks in MongoDB, ensuring job status integrity.