Ethereum Goerli Testnet Just Replaced by Holesky: What You Need to Know

Ethereum (ETH), the second largest blockchain and the most mainstream smart contracts platform, has accomplished a major milestone. The history of its most important testnet, Goerli, has come to an end.

Here's why Ethereans decided to sunset Goerli in 2023 and what is special about Holesky, Goerli's hotly anticipated successor.

Ethereum replaces Goerli testnet by Holesky: Basics

Today, Sept. 15, 2023, on the first anniversary of The Merge activation in mainnet, Ethereum (ETH) has ceased supporting its testnet, Goerli. Developers need to migrate toward Holesky, the first PoS-by-design testnet.

• Holesky (or Holešky, Holešovice) is an Ethereum (ETH) test network (testnet) activated on Sept. 15, 2023.
• Holesky replaces Goerli as a staking, infrastructure and protocol-developer testnet.
• For dApp stress tests, smart contract experiments and other EVM-related procedures, developers should refer to Sepolia testnet.
• Holesky is the first-ever Ethereum (ETH) testnet launched on the top of the proof-of-stake (PoS) consensus.
• Holesky launches to address scalability issues of Goerli: the shortage of goETH testnet tokens, the low number of validators and so on.
• Holesky will have 1.46 million validators, which is almost twice as much as Ethereum (ETH) mainnet has.
• New testnet support will be abandoned by 2028.

As such, with Holesky, Ethereum (ETH) developers will have a new sandbox environment in which to experiment with various features of the protocol.

What is testnet?

In cryptocurrencies, a test network or testnet is an experimental distributed network that emulates the processes that happen on a cryptocurrency network, but with no real value transferred. Just as with main networks (mainnets), accounts can send tokens to each other, while validators confirm them by adding new blocks to the chain.

Users of a testnet get "play" tokens from faucets, a free-to-use mechanism created by Ethereum (ETH) enthusiasts. For instance, some faucets distribute free testnet Ethers for sharing Twitter accounts, connecting to Discord and so on.

Such networks are necessary for stress testing dApps without the risks of losing money. Every modern DeFi or wallet undergoes a testnet phase before mainnet deployment.

Ropsten, Rinkeby, Goerli, Sepolia: Crucial Ethereum (ETH) testnets

Ethereum (ETH), the second largest blockchain and the first programmable network (with smart contracts), used a couple of testnets during its eight-year history. Launched in 2016, Ropsten replaced Morden, the first-ever testnet for proof-of-work (PoW) Ethereum. Ropsten was a testbed of all major Ethereum (ETH) dApps we are using and the first testnet to be "merged" when Ethereum (ETH) tested the PoW-to-PoS transition.

In 2017, Ethereans launched Rinkeby, a testnet on the top of the Clique proof-of-authority (PoA) consensus mechanism, which is a modified version of proof of stake (Pos). It only interacted with the Go Ethereum (Geth) version of client software.

At the ETH Berlin Conference in 2018, Ethereum (ETH) developers unveiled Goerli, a multiclient Ethereum (ETH) testnet. It means that it could work with the versions of Ethereum (ETH) software written in various programming languages.

Finally, in 2021, Ethereum Sepolia testnet was launched with an unlimited number of testnet tokens. 

Introducing Holesky, very special Ethereum (ETH) testnet

Activated today, Ethereum's Holesky is an attempt by core developers to address all the issues that somehow affected previous testnets and their usage by teams.

Holesky: Highlights

Holesky is the first long-standing public Ethereum testnet that is "merged from genesis"; this means that Holesky never had a proof-of-work (PoW) version. Not unlike its predecessors, Holesky draws its name from the Nádraží Holešovice subway station in Prague.

Holesky works together with Sepolia; while the first testnet is designed to be a technical platform for experiments with staking designs, the general infrastructure of Ethereum (ETH) and protocol-level development ideas, Sepolia is a platform for testing smart contracts, decentralized applications and all EVM functionalities. Like all  mainstream crypto testnets, Holesky will have its own set of validators, block explorer and ecosystem of faucets.

Holesky: What was wrong with Goerli?

Holesky goes live to replace Goerli, a major Ethereum (ETH) testnet since 2018. Holesky is designed to help Ethereum (ETH) testers avoid the disadvantages of earlier testnets. For instance, Ethereum Goerli users faced a shortage of GoETH test tokens and were even forced to purchase them for money, which is in contradiction of Ethereum (ETH) testnet rules. Holesky is unlikely to face similar issues.

Also, it will have a previously unimaginable number of validators: 1.46 million entities will protect network integrity. This is more than Ethereum’s mainnet (700,000) and Goerli (512,000) have in all. This, in turn, will allow developers to mimic "real-world" Ethereum (ETH) operations closely.

Per the creators of Holesky, they allocated over two billion HoleskyETH by the launch in order to make this quantity sufficient for all developers.

Holesky: Specifications

Holesky goes live with a set of specifications just like any other EVM ecosystem blockchain. Here's what future Holesky users should consider before getting connected to the network.