A condensed version of our full Hyperliquid testnet guide , which also covers HyperEVM gas, every error message we hit and a pre-mainnet checklist. Hyperliquid's testnet lets you trade with mock USDC, so you can test order logic and signing before real money is involved. This is the short path: the addresses, test funds, one working order, and the five things that will break when you switch to mainnet. 1. The addresses you need What Testnet Mainnet API (...