Dear Celo Community,
Celo’s testing environment is getting a major makeover. With Holesky sunsetting on September 30, 2025, we are excited to introduce Celo Sepolia, a clean, streamlined Ethereum L2 testnet connected to Sepolia that features Celo’s cutting edge features.
With Holesky sunsetting, the Baklava and Alfajores testnets which both sit under Holesky will be deprecated. Over the next month, the Celo community will transition from Baklava and Alfajores to this new testnet, ensuring developers, node operators, and infrastructure providers have a faster, easier way to build and test. From oracles and explorers to node providers and dApps, our earliest adopters are already putting Celo Sepolia to work.
Migration Timeline
The planned transition period runs from August 14 to September 14, 2025. During this time, partners, node operators, and developers should complete their migration to Celo Sepolia.
On September 30, 2025, Holesky will be sunset, marking the official end of support for Baklava and Alfajores. From that point forward, all testing and integrations should take place on Celo Sepolia.
Why the Change
This migration keeps Celo in step with Ethereum’s evolving testnet strategy, reduces the complexity of maintaining legacy networks, and offers developers a faster, cleaner environment with no inherited state from Alfajores or Baklava. Celo Sepolia is built on Ethereum Sepolia and powered by EigenDA v2 (Blazar), providing improved sync times and seamless compatibility with Ethereum-native tooling.
Early Adopters
The first wave of partners helping bring Celo Sepolia to life includes:
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Google Cloud – Google Faucet Integration
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Blockscout – Blockchain Explorer
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EigenDA v2 – Data Availability
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Superbridge – Bridging Infrastructure
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Ankr – Node Provider
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DSRV – Node Provider
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Forno – Node Provider
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Redstone – Oracle Services
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Talent Protocol – Web3 Professional Network
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Prosperity Pass – Celo PG Onchain Access Pass
If you are already live, please let us know so we can feature you in future updates.
Key Information for Migration
Celo Sepolia has Chain ID 11142220, is live now, and starts with a clean slate (no historical data or contracts carried over from Alfajores). Developers should confirm dependencies are supporting Celo Sepolia, redeploy contracts, and confirm tooling support. Node providers are encouraged to support both Alfajores and Celo Sepolia during the transition to ensure a smooth migration.
Resources
Full migration instructions, setup guides, and technical details are available in the Celo Sepolia Launch Guide. For support, please reach out in the #celo-L2-support channel on Discord.
Celo Sepolia marks the beginning of a faster, cleaner, and more connected testing environment for the Celo community. Thank you to our partners and community members for your support during this transition.
The cLabs Team