Get started with Celo Sepolia Testnet (Celo’s Developer Testnet).

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What is the Celo Sepolia Testnet?

The Celo Sepolia Testnet is Celo’s new developer testnet built on Ethereum Sepolia, designed to replace Alfajores following the planned Holesky deprecation in September 2025. This testnet provides a stable environment for developers to build, test, and deploy decentralized applications before launching on Mainnet. Developers can access testnet funds via the faucet, interact with smart contracts, and experiment with wallets, dApps, and node operations without financial risk. Key Details:
  • Chain ID: 11142220
  • L1 Foundation: Built on Ethereum Sepolia
  • Fresh State: Starts with a clean slate, no state inheritance from Alfajores
  • Functionality: Provides the same developer experience as Alfajores
The full network information is available in the network overview.
New Celo Sepolia Testnet Now Live!Try Celo’s new developer testnet on Ethereum Sepolia. Learn more →
The Celo Sepolia Testnet is designed for testing and experimentation by developers. Its tokens hold no real world economic value. The testnet software will be upgraded on a regular basis. You may encounter bugs and limitations with the software and documentation.
Please help the community to improve Celo by asking questions on the Forum!

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Migration from Alfajores

For developers currently using Alfajores, consider the following when migrating to Celo Sepolia:
  • New Chain ID: Update applications to support chain ID 11142220
  • Fresh State: All contracts will need to be redeployed
  • Parallel Operation: Both testnets will run simultaneously during the transition period
  • Testing Environment: Begin testing applications on Celo Sepolia in preparation for the Alfajores sunset

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Network Configuration

For detailed network configuration including RPC endpoints, contract addresses, and P2P peer information, see the Running a Node guide.