Note: The ENS App and ENS Explorer are both currently on Sepolia testnet. Behaviour and available features may change before mainnet.
Gas is the network fee Ethereum charges to process a transaction. It is paid in ETH from your connected wallet, and it goes to the network, not to ENS.
Any onchain change costs gas: registering a name, renewing it, transferring it, or saving changes to its records. Signing in with your wallet is free.
There is no fixed price. The fee rises and falls with network demand, so your wallet shows the exact fee before you approve each transaction.
With Smart Sessions on, gas still comes out of your wallet. Turning it on funds a session account from your wallet, and that account pays the gas for what it signs. Keep some ETH in your wallet before you start.
Both apps run on Sepolia testnet, so gas is paid in Sepolia ETH rather than real ETH. A Sepolia faucet gives you test ETH free. ENS Explorer funds a fresh wallet with test stablecoins for payments, but gas is separate — you still need Sepolia ETH.