Building a Trading Card Price Tracker with Free APIs

Building a Trading Card Price Tracker with Free APIs If you collect trading cards -- Pokemon, Magic: The Gathering, Yu-Gi-Oh -- you know the pain of checking prices manually. You also know that a card's market price only tells half the story. The other half is scarcity: how many PSA 10 copies exist? In this tutorial, we will build a Node.js script that: Looks up current market prices from TCGPlayer Pulls graded population data from PSA Combines them into a price-to-scarcity ratio Sends alerts when undervalued cards are found Total code: about 50 lines. Total cost: $0. Prerequisites Node.js 18+ installed A text editor Optional: a Slack workspace for alerts Step 1: Fetch TCGPlayer Prices The TCGPlayer API returns current market prices, lowest listings, and card metadata. Here is how to search for a card: const BACKEND = " https://rapidapi-backend-production.up.railway.app " ; async function getCardPrices ( cardName ) { const res = await fetch ( ` ${ BACKEND } /tcgplayer/search?query= ${