Current faucet requirement
To use the official faucet, the same wallet address must first have deposited on mainnet. The faucet at app.hyperliquid-testnet.xyz/drip currently distributes 1,000 mock USDC for testing.
The requirement does not make testnet funds real or redeemable. Never pay someone for faucet assets and never send real capital to a testnet address.
Email login can use different addresses
The official documentation warns that email onboarding can generate different wallet addresses on mainnet and testnet. That breaks the same-address faucet requirement unless the mainnet email wallet is exported and connected separately.
Exporting reveals a private key. Use a secure device, never paste it into a website and consider whether a dedicated development wallet is safer than reusing an account with meaningful funds.
Separate every environment value
Keep mainnet and testnet HTTP endpoints, WebSocket endpoints, chain IDs, keys and asset identifiers in explicit configuration. A safe application should fail closed when an environment variable is missing rather than defaulting to mainnet.
Use visible network labels in logs and interfaces. Test order placement, cancellation, reconnects, reduce-only behavior and error handling before enabling any real-money signing path.
What testnet cannot prove
Testnet can validate signatures, request shapes and state transitions. It cannot reproduce mainnet liquidity, slippage, congestion, fills, funding regimes or economic incentives.
After testnet, run a minimal mainnet lifecycle with small size and strict limits. A successful mock fill is not evidence that a production strategy is profitable or safe.