Ethereum is retiring the Holešky testnet in late September 2025 and replacing it with the new Hoodi testnet; developers will shift long-term validator testing to Sepolia and short-term trials to Ephemery, preparing the network for the Fusaka hard fork and future Glamsterdam upgrades.
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Holešky shutdown confirmed: planned wind-down two weeks after Fusaka test completion.
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Hoodi will replace Holešky as a long-term staging testnet while Sepolia remains primary for dApp testing.
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Fusaka (Nov 2025) and Glamsterdam (2026) aim to improve rollup data access and block times.
Holešky shutdown: Ethereum retires Holešky in Sept 2025, migrating tests to Hoodi and Sepolia — learn what developers must do next. Read more from COINOTAG.
What is the Holešky shutdown and why is it happening?
Holešky shutdown is a planned retirement of Ethereum’s largest public testnet after two years of use. Developers will retire Holešky once Fusaka test workloads complete to consolidate testing on newer, more reliable environments and reduce maintenance overhead.
How will the transition to Hoodi work?
Developers will phase validators and integration tests from Holešky to Hoodi in stages. Sepolia will remain the primary testnet for dApp developers, while Ephemery will be used for short-lived validator experiments. The transition aims to keep validator counts stable and preserve test coverage.
“The network served its purpose, enabling thousands of validators to test protocol upgrades, including the Dencun network upgrade and most recently, Pectra…” — Ethereum Foundation blog (plain text reference)
Source: blog.ethereum.org
When will Holešky be retired and how does this align with Fusaka?
Holešky will close roughly two weeks after the Fusaka test sequence completes, targeted for late September 2025. Fusaka itself is scheduled for mainnet deployment in early November 2025, so the testnet shutdown precedes the mainnet upgrade to ensure smoother rollout and final validation.
What does Fusaka change for rollups and validators?
Fusaka (Fulu-Osaka) redistributes rollup data access across validators to reduce per-node load. Expected benefits include lighter node operation, improved decentralization, and faster, cheaper layer-2 transaction processing.
How will Glamsterdam affect Ethereum after Fusaka?
Glamsterdam, targeted for 2026 under EIP-7782, may reduce block times to six seconds and adjust validation mechanics to better support zero-knowledge proofs. These changes are intended to further scale rollups and zk-based systems.
Testnet roles: quick comparison
| Testnet | Primary role | Duration |
|---|---|---|
| Holešky | Large-scale upgrade stress testing | Retiring Sept 2025 |
| Hoodi | Replacement long-term staging environment | Active from transition |
| Sepolia | dApp integration and developer testing | Ongoing |
| Ephemery | Short-term validator experiments | Ongoing |
Frequently Asked Questions
Will validators need to move their keys from Holešky to Hoodi?
Validators should follow developer migration guides; keys generally stay local, but testnet genesis and configuration will change. Confirm settings and client versions before switching to Hoodi.
Is Sepolia still safe for dApp testing?
Yes. Sepolia remains the recommended testnet for application-level testing, while Hoodi and Ephemery cover validator and stress scenarios.
Key Takeaways
- Planned retirement: Holešky will be retired in late September 2025 following Fusaka tests.
- Hoodi replacement: Hoodi becomes the primary long-term staging testnet; Sepolia stays for dApp testing.
- Upgrade roadmap: Fusaka (Nov 2025) improves rollup data access; Glamsterdam (2026) targets block-time and validation changes.
Conclusion
Ethereum’s decision to retire Holešky and move to Hoodi reflects a deliberate effort to streamline testing ahead of Fusaka and Glamsterdam. Developers should prepare by validating client versions, migrating tests to Hoodi and Sepolia, and monitoring official Ethereum Foundation communications (blog.ethereum.org) for exact timelines. COINOTAG will update as changes are finalized.
