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Celo Sepolia is the developer testnet that replaced Alfajores after Ethereum deprecated Holesky in 2025. Baklava was retired at the same time, with no replacement.
Key Information
  • Chain ID: 11142220
  • Status: testnet live
  • Built on: Ethereum Sepolia L1
  • Phases:
    • Jul 23, 2025: Celo Sepolia launch ✅
    • Jul 24, 2025—Jul 31, 2025: Internal testing ✅
    • Aug 1, 2025—Aug 12, 2025: Early access phase ✅
    • Aug 13, 2025: Public announcement ✅
    • Aug 14, 2025—Sep 14, 2025: Transition period ✅
    • Sep 30, 2025: End of support for Alfajores and Baklava ✅
Node Providers: Alfajores and Baklava are retired; support Celo Sepolia.Developers: Verify that your dependencies support Celo Sepolia, then go ahead and deploy all contracts.

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What is Celo Sepolia?

Celo Sepolia is the new developer testnet for Celo running as an Ethereum Layer 2 on Sepolia. It starts with a clean slate (no inherited state from Alfajores) and is designed for long-term use following Ethereum Sepolia’s testnet lifecycle.

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Call to Action

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For Node Providers

Node providers were asked to support both Alfajores and Celo Sepolia in parallel during the early access and transition phases to ensure a smooth migration for developers. Alfajores and Baklava are retired, so only Celo Sepolia needs support. See the node setup guide for technical details and our recommended Docker Compose Setup. The versions released for the Celo Sepolia launch were op-geth v2.1.2, op-node v2.1.0 and eigenda-proxy v1.8.2. For current versions see Network config.

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For Developers

  • Update applications to support chain ID 11142220.
  • Redeploy contracts on Celo Sepolia.
  • Get testnet CELO tokens from the faucets.
Since Celo Sepolia starts with a clean slate, there is no historical data or contracts carried over from Alfajores, providing a pristine testing environment.

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Key Characteristics and Resources

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Key Differences from Alfajores

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Early Adopters

Thank you to the first wave of our ecosystem partners supporting Celo Sepolia already:
  • Google Cloud – Google Cloud Web3 Faucet
  • Blockscout – Block Explorer
  • EigenDA v2 – Data Availability
  • Superbridge – Bridging Infrastructure
  • Ankr – Node & RPC Provider
  • AllThatNode by DSRV – Node & RPC Provider
  • Redstone – Oracle Services
  • Talent Protocol – Web3 Professional Network
  • Prosperity Pass – Celo PG Onchain Access Pass

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Getting help

Ask in #celo-L2-support on Discord if you have any questions.