MarginCanary
Track your dropshipping supplier's product pages and get an email alert the
moment the price changes, a product goes out of stock, comes back in stock,
or your profit margin drops below a threshold you set (enter what you sell
the product for, and MarginCanary alerts you when a supplier price hike eats
into your margin — not just when the raw price moves).
If you have zero coding experience, start with DEPLOYMENT_GUIDE.md — it
walks through getting this live on the internet for free, step by step,
using only web dashboards (no software to install, no command line).
What's in this project
app/ — the website itself (Next.js: landing page, login/signup, dashboard)components/ — reusable UI pieces (product card, add-product form, chart)lib/ — the actual logic: the scraper, the email sender, the Supabase
database connectionssupabase/schema.sql — the database structure, run this once in Supabasesupabase/schema-margin.sql — adds sell price + margin alert threshold,
run this once too (after schema.sql)supabase/schema-billing.sql — adds each user's plan and Stripe IDs; run
this once after schema-margin.sqlsupabase/schema-checks.sql — adds shipping and fees per sale, tracks when
each product was last checked, and limits which columns users can edit;
run this once after the other schema filessupabase/schema-security.sql — makes the database enforce the plan
limit and the alert recipient, and keeps check results server-only; run
this last (safe to re-run).github/workflows/cron.yml — the free scheduler that checks all products
automatically every 6 hours
Stack (100% free tier)
| Piece | Tool | Free tier |
|---|
| Hosting | Vercel | Yes, generous Hobby plan |
| Database + auth | Supabase | Yes, 500MB DB |
| Email alerts | Resend | Yes, 3,000 emails/month |
| Scheduler | GitHub Actions | Yes, free for personal repos |
Local development (optional — only if you later want to code)
npm install
cp .env.example .env.local # fill in your real keys
npm run dev
