Building a simple crypto data tool with APIs, blockchain nodes, and open-source libraries
Most beginner tutorials treat “get crypto data” as one problem with one solution: call an API, done. It’s actually two separate problems wearing the same trench coat. Market data — prices, volume, market cap — comes from centralized APIs like CoinGecko or CoinMarketCap. On-chain data — actual transactions, wallet balances, smart contract state — comes










