Ethereum is preparing to sunset its largest testnet, Holesky, after two years of service. The decision follows the upcoming Fusaka upgrade, which promises to make rollups cheaper and faster by distributing data storage more evenly across validators. While Holesky was once considered the backbone for large-scale testing, ongoing technical challenges have pushed developers to transition toward newer and more efficient testnets.
Why Holesky Mattered
started in 2023, Holesky quickly became Ethereum’s largest public testnet, designed to stress-test the network’s proof-of-stake (PoS) system at scale. Unlike smaller testnets, Holesky supported thousands of validators, making it an essential environment for trialing upgrades before mainnet deployment.
During its lifespan, Holesky played a pivotal role in preparing Ethereum for major milestones such as the Dencun and Pectra upgrades. These updates were critical for reducing transaction costs, improving validator performance, and enhancing Ethereum’s scalability roadmap. In many ways, Holesky helped ensure that Ethereum’s transition into a fully scalable ecosystem could proceed smoothly.
The Problems That Emerged
Despite its early successes, Holesky began to struggle in 2025. After the Pectra upgrade, the network started experiencing “inactivity leaks” — a condition where large numbers of validators went offline simultaneously. This created severe congestion for validators attempting to exit, with exit queues stretching out for months.
For developers who relied on rapid testing and short feedback loops, Holesky’s sluggish performance became more of a bottleneck than a solution. The inability to properly test the validator lifecycle in real-time undermined its usefulness as Ethereum’s primary staging ground.
The Fusaka Upgrade: A Turning Point
The decision to wind down Holesky comes in tandem with Ethereum’s Fusaka upgrade, expected later this year. Fusaka is designed to optimize rollups — Ethereum’s primary scaling mechanism — by redistributing the network’s data storage responsibilities more evenly across validators.
This upgrade aims to significantly reduce the costs associated with rollups, making them faster and more affordable for both developers and end users. Once Fusaka is finalized, Ethereum core teams will shift their focus toward supporting new and more efficient testnets, effectively marking the end of Holesky’s relevance.
The Holesky shutdown will occur two weeks after Fusaka goes live, at which point client and infrastructure teams will cease all support.
Enter Hoodi: The New Testnet
To replace Holesky, Ethereum started the Hoodi testnet in March 2025. Hoodi is a clean-slate project, designed to sidestep the validator exit issues that plagued Holesky. It is already being positioned as the primary testnet for validator and staking provider experiments.
By providing a fresh infrastructure with more flexibility, Hoodi ensures developers can test validator behavior, staking protocols, and network resilience under high-load conditions without the same bottlenecks.
Alongside Hoodi, Ethereum maintains two other active testnets:
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Sepolia: The main environment for testing decentralized applications (dApps) and smart contracts.
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Ephemery: A quick-reset testnet that restarts every 28 days, offering developers a rapid cycle for validator testing.
This multi-testnet approach provides Ethereum with specialized environments tailored to different testing needs, replacing Holesky’s one-size-fits-all role.
Lessons from Holesky’s Shutdown
Holesky’s closure underscores the challenges of running large-scale testnets over long periods. While it was highly successful in preparing Ethereum for critical upgrades, its eventual decline highlights the need for adaptable, resettable, and specialized test environments.
Ethereum’s strategy now leans toward smaller, purpose-driven testnets rather than relying on a single, massive network. This approach not only reduces bottlenecks but also ensures developers can get faster feedback while testing different aspects of the ecosystem.
Market Context: ETH Steady Amid Transition
Despite the changes in Ethereum’s infrastructure, the market impact appears minimal for now. Ether (ETH) was trading at $4,380 in Asian morning hours on Tuesday, holding steady with little movement over the past 24 hours.
Investors seem more focused on Ethereum’s scaling roadmap and the long-term benefits of upgrades like Fusaka than on the operational changes to its testnet landscape. The move away from Holesky is being viewed as a natural evolution in Ethereum’s development process rather than a setback.
Conclusion: A Step Forward in Ethereum’s Evolution
The shutdown of Holesky marks the end of an important chapter in Ethereum’s development history. For two years, it served as the proving ground for upgrades that shaped the network’s scalability and efficiency. However, as Ethereum matures, the need for more agile and specialized testnets has taken priority.
With Fusaka promising to bring faster and cheaper rollups, and with Hoodi, Sepolia, and Ephemery ready to serve diverse testing roles, Ethereum is positioning itself for the next wave of growth. Holesky may be closing, but its legacy will live on in the lessons it provided — paving the way for a more resilient and scalable blockchain ecosystem.
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