Build a Crypto Portfolio Tracker in Under 50 Lines of Code

You want to track your crypto portfolio but don't want to build an entire backend or deal with CoinGecko rate limits. Here's how to build a working portfolio tracker in under 50 lines of JavaScript. No API key needed. No signup. Just code. What We're Building A command-line portfolio tracker that: Fetches live prices for any coins you hold Calculates your total portfolio value in USD Shows profit/loss per coin Runs with a single node portfolio.js command The API We'll use the Frostbyte API — it returns real-time prices for 500+ coins with no authentication required. Quick test: curl -s https://agent-gateway-kappa.vercel.app/prices | python3 -m json.tool | head -20 Response: { "count" : 527 , "prices" : { "BTC" : "71312.5" , "ETH" : "2080.95" , "SOL" : "88.80" , "DOGE" : "0.094" , "XMR" : "363.8" } } 527 coins, updated in real time, zero authentication. Step 1: Define Your Holdings Create portfolio.js : const HOLDINGS = [ { coin : ' BTC ' , amount : 0.5 , buyPrice : 42000 }, { coin : '