Getting testnet keys

bash

stellar keys generate --network testnet <name>
stellar keys address <name>
stellar keys show <name>

Fund an account through friendbot:

bash

curl "https://friendbot.stellar.org/?addr=<G...>"

COMMITMENT_SECRET_HEX is a raw ed25519 seed in hex, not a Stellar S... string — it signs channel commitments directly rather than transactions.

For Base Sepolia, EVM_PRIVATE_KEY is a raw private key, 0x followed by 64 hex characters, from any EVM wallet or viem's generatePrivateKey(). The payer needs Base Sepolia USDC, from https://faucet.circle.com, and no ETH: the facilitator pays the gas (the exact scheme's EIP-3009 method). A wrong or malformed key is reported at PREFLIGHT before anything is sent, without echoing it.