Ethereum to retire Holešky testnet in two weeks

Ethereum will retire its largest public testnet, Holešky, in two weeks, with validators and infrastructure teams preparing to migrate to Hoodi. The closure streamlines testing into specialized lanes, reflecting the protocol’s more mature and segmented operational needs.

On September 1, the Ethereum Foundation’s Protocol Support team announced the formal two-week countdown to sunset the Holešky testnet, marking the end of one of the protocol’s largest public testing environments.

The team said the process will begin once the Fusaka upgrade finalizes on the network, forcing client teams to power down the vast majority of validator nodes. After this period, Holešky will enter a completely unsupported state, with no further maintenance or infrastructure provided by core development teams.

Holešky’s legacy and Ethereum’s testnet evolution

Launched in 2023, Holešky’s architecture was designed to support a massive validator set, enabling infrastructure providers and staking services to stress-test protocol upgrades like Dencun and Pectra under conditions that closely mimicked the mainnet.

This scale was its greatest asset, providing an unparalleled environment to simulate the chaos and complexity of real-world validator operations before deploying changes to the live blockchain. However, that very scale ultimately revealed a critical flaw.

According to the foundation, prolonged inactivity leaks following the Pectra activation in early 2025 created a huge exit queue for validators. While the network eventually finalized, the drawn-out exit process exposed a practical limitation: testing the full validator lifecycle in a timely manner had become increasingly difficult.

To address these challenges, the foundation introduced Hoodi in March 2025, a fresh testnet environment designed to handle validator operations efficiently while supporting all Pectra features and future upgrades, including Fusaka.

Migration path

The foundation has outlined a clear migration path for projects still operating on Holešky. Staking operators and node infrastructure providers are directed to transition their testing operations to Hoodi.

Meanwhile, application and smart contract developers who had been using Holešky are advised to pivot to the Sepolia testnet, which remains the recommended environment for dApp and tooling development.

Holešky’s retirement formalizes a new, streamlined triage of Ethereum testnets. The ecosystem will now lean on three specialized environments. These include Sepolia for general application development, Hoodi for large-scale validator and infrastructure testing, and Ephemery for focused, rapid validator lifecycle tests that reset every 28 days.