Build idea · Intermediate
A price-tracker
Watch prices so you don't have to — and get pinged the moment something drops.
A price-tracker lets you paste in a product URL, then quietly checks that page on a schedule and stores every price it sees. The core feature is the drop alert: when a tracked item falls below your target (or just dips from its last reading), you get an email with the old price, the new price, and a link to buy. It's the classic "boring but genuinely useful" project — you'll actually use it.
What you'll learn
- →Running scheduled background jobs with cron and making them idempotent, so a missed or double run doesn't corrupt your data or spam you
- →Fetching and parsing a real webpage's price reliably — dealing with markup that changes, missing selectors, and requests that fail, without the whole job dying
- →Modeling price history as time-series rows and writing the query that decides 'is this actually a drop worth alerting on?'
- →Sending transactional email that lands in the inbox, and only firing an alert once per drop instead of on every check
Take it further
- +Add a price-history chart per product (Recharts) so users can see the trend and judge whether today's price is actually good
- +Build a one-click browser extension that grabs the current page URL and adds it to your tracker, instead of copy-pasting links
- +Support target rules beyond a fixed price — 'alert me at 20% off the highest price I've seen' or 'lowest in 90 days' — and compare the same item across multiple retailers