The tradition of naming Ethereum testnets after train stations continues with the name “Holesky,” derived from Nádraží Holešovice, a subway station in Prague.
There are two commonly used Ethereum testnets: Goerli and Sepolia. Goerli, the older one, was introduced in 2019 and has since become a popular testing environment among Ethereum developers. Offering a space for experimenting, Goerli is used to test new ideas without incurring gas fees and to fix bugs before deploying them on the Mainnet.
While Goerli has been invaluable for the Ethereum ecosystem’s development, this testnet will stop functioning in January 2024. In recent months, the Ethereum Foundation has encouraged developers to transition to the newer Sepolia.
However, before that, a new testnet will join the family. In a recent meeting, Ethereum’s core developers confirmed that Holesky will be launched in September. While Holesky largely resembles Sepolia in design, it’s intended to be more extensively used for infrastructure and protocol development. Meanwhile, Sepolia will remain the testing ground for Ethereum-based applications.
One of the key advantages of Ethereum testnets is that they operate on parallel currencies instead of Mainnet ETH. For instance, Goerli uses GoETH. Testnet tokens are available for developers at no cost. However, on Goerli, their distribution can sometimes be congested. Due to the limited supply of GoETH, most Goerli Faucets restrict the amount developers can receive daily.
To tackle this issue, Sepolia has no hard cap on the total circulating token supply. Hence, Faucet providers can offer developers a much larger amount of SepETH.
Unlike Sepolia, Holesky will have a fixed testnet token supply. However, at 1.6 billion tokens, the cap will still be much higher compared to the total supply of Mainnet ETH, which is currently around 120 million.