Key Notes
Holesky testnet served developers for two years, enabling thousands of validators to test protocol upgrades successfully.
Critical downtime during Pectra testing in early 2025 exposed smart contract address issues, prompting infrastructure changes.
Developers have two weeks post-Fusaka launch in November to migrate from Holesky to supported testnets like Hoodi and Sepolia.
The Ethereum Foundation announced on Sept. 1 that the Holesky testnet will shut down in the coming weeks as it reaches its planned sunset date ahead of the impending “Fusaka” network upgrade.
Holesky was launched back in Sept. 2023 to allow developers a safe environment to roll out upgraded features and services on the Ethereum blockchain network. During its two-year tenure, it was primarily used to test staking infrastructure and validator operations at scale.
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According to a blog post from the Ethereum Foundation, the Holesky testing network served its purpose by enabling thousands of validators to test protocol upgrades, including the Dencun network upgrade and the recently integrated Pectra upgrade.
Holesky’s Critical Failures Paved Way for New Testing Framework
While testing Pectra in February and March of 2025, Holesky suffered critical downtime issues related to the network’s failure to specify correct smart contract addresses for Pectra Request Hash Calculations, causing post-launch disruption and finalization delays.
These issues led to the launch of the Hoodi testnet in March and contributed to the next phase of Ethereum development by allowing developers to identify key issues ahead of global user base rollouts for the latest upgrade.
The Ethereum Foundation is now directing developers to migrate all functionality away from Holesky and toward the Hoodi environment as the planned sunset kicks off starting Sept. 1.
According to the Foundation, once the upcoming Fusaka upgrade goes live in November, any validator nodes still operating on the Holesky testnet will have two weeks to migrate to one of the remaining testnets. After this period, Holesky will no longer be supported by client, testing, or infrastructure teams.
These will include Sepolia, an application and tooling testbed; Ephemery, a lightweight validator lifecycle testbed that resets every 28 days; and the aforementioned Hoodi testnet, which serves as the primary testing ground for developers going forward.
