Celo Sepolia Testnet Launch
Celo Sepolia is a new developer testnet that will replace Alfajores when Holesky sunsets in September 2025. The Baklava testnet will also sunset with Holesky, with no replacement planned.
This page will be kept updated with key information about the transition.
- 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: Planned Alfajores and Baklava sunset, aligned with Holesky deprecation
Node Providers: Please support both Alfajores and Celo Sepolia during the transition period.
Developers: Verify that your dependencies support Celo Sepolia, then go ahead and deploy all contracts.
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.
Call to Action
For Node Providers
Please support both Alfajores and Celo Sepolia in parallel during the early access and transition phases to ensure a smooth migration for developers. See the node setup guide for technical details and our recommended Docker Compose Setup.
Release versions:
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.
Key Characteristics and Resources
- Chain ID: 11142220
- L1 Foundation: Ethereum Sepolia
- EigenDA: v2 (Blazar)
- Contracts: see the L1 and L2 contracts in the specification
- RPC endpoint: Celo Sepolia Forno
- Block explorer: Blockscout
- Faucets:
- Bridge: Superbridge for Celo Sepolia
Key Differences from Alfajores
| Aspect | Alfajores | Celo Sepolia |
|---|---|---|
| L1 Foundation | Ethereum Holesky | Ethereum Sepolia |
| Chain ID | 44787 | 11142220 |
| State | Historical from L1 migration | Fresh start |
| Longevity | Sunset planned Sept 2025 | Long-term testnet |
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
Getting Help
Please reach out to our team on Discord in the #celo-L2-support channel if you have any questions.