I Built a Price Monitoring System in 30 Minutes — Here's the Stack (All Free APIs)

Last month, a friend running a small e-commerce store asked me: "How do big companies track competitor prices? I can't afford $500/month tools." I told him I'd build one for free. It took 30 minutes. Here's exactly how I did it — and you can copy this approach for any niche. Full code on GitHub: price-monitoring-free The Problem Price monitoring tools like Prisync ($99-399/mo) or Competera ($1000+/mo) are built for enterprises. Small business owners need something simpler: Track 10-50 products across 3-5 competitor sites Get notified when prices change See price history over time The Architecture (Dead Simple) ┌─────────────┐ ┌──────────────┐ ┌─────────────┐ │ Scheduler │────▶│ Scraper API │────▶│ JSON Store │ │ (cron/n8n) │ │ (sitemap + │ │ (GitHub) │ │ │ │ product │ │ │ └─────────────┘ │ pages) │ └──────┬──────┘ └──────────────┘ │ ┌────▼─────┐ │ Notifier │ │ (webhook) │ └──────────┘ Step 1: Find Product URLs via Sitemap API Most e-commerce sites expose their product URLs in XML sitem