Celo as an Ethereum L2: A Frontier Chain for Global Impact

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On March 25, 2025, Celo officially completed its transition from a Layer 1 blockchain to an Ethereum Layer 2, a pivotal leap forward in our mission to scale real-world impact through open, inclusive, and Ethereum-aligned infrastructure.

This was more than a technical milestone. It was a turning point.

Celo now inherits the power of Ethereum security, faster finality, low fees, native bridging, and deep liquidity, while preserving what makes Celo unique: mobile-forward accessibility, community-driven innovation, and a continued focus on real-world use cases unlocking prosperity for all. Not only is chain revenue up since the start of the year, close to 50% of all transaction fees are now being paid directly with tokens leveraging fee abstraction, primarily with USDT. Developers also gain access to Ethereum’s full suite of tools, including deeper composability with Ethereum-native apps.

Now that Celo is live as an Ethereum L2, the focus turns to what comes next, and how best to hyperscale the network, strengthen infrastructure, and unlock new mini apps and use cases for developers and users on the road to a trillion-dollar onchain economy.

This post outlines several upcoming milestones that will shape the next phase of Celo’s growth as a frontier chain for global markets — including protocol upgrades like Isthmus to integrations like EigenDA v2, Succinct, and more.

This is only the beginning, and the community is invited to help shape what comes next.

Upcoming Milestones

Isthmus: Activating the Next Hardfork on Celo L2

Isthmus is the next major upgrade for Celo as an Ethereum L2, bringing the L2 stack in line with Ethereum’s Pectra upgrade and introducing key improvements to scalability, interoperability, and fault proof security.

Key Activation Dates (Tentative)

  • Baklava Testnet: Timestamp 1749654000 on Wednesday, June 11, 2025, 15:00 UTC
  • Alfajores Testnet: Timestamp 1750863600 on Wednesday, June 25, 2025, 15:00 UTC
  • Mainnet Activation: Timestamp 1752073200 on Wednesday, July 9, 2025, 15:00 UTC

What’s Included

Isthmus implements the Prague features from Ethereum’s recent Pectra hardfork into the OP Stack. This includes the following notable EIPs:

In addition, Isthmus introduces the L2 Withdrawals Root in the Block Header, which lowers the operational lift for chain operators and improves scalability as the number of Superchain participants grows.

The upcoming Isthmus hardfork will include the Holocene Hardfork features, as the Celo L2 migration was finalized before Holoscene. These features include:

  • Holocene Block Derivation: Streamlines the derivation pipeline for better fault proof performance and cross-chain interoperability.
  • EIP-1559 Configurability: Makes gas target and gas limit independently configurable via the SystemConfig L1 contract, allowing for better tuning of fee markets.

For a deep dive into the technical details, see OP Labs’ Isthmus and Holocene specifications.

Isthmus is a foundational upgrade that ensures Celo remains aligned with Ethereum core developments while unlocking improvements in efficiency, decentralization, and Superchain compatibility. As we scale, these upgrades help simplify infrastructure and prepare Celo for future innovation across the Ethereum ecosystem.

EigenDA v2: Faster, More Reliable Data Availability for Celo

As part of Celo’s continued growth as an Ethereum L2, the cLabs team is preparing to integrate EigenDA v2, also known as Blazar, to further innovate and strengthen the network’s data availability layer.

Blazar represents a major architectural upgrade to the EigenDA protocol, introducing improved system throughput and stability, alongside new capabilities like permissionless DA payments and enhanced resource throttling. These updates bring meaningful improvements to performance, security, and reliability.

Most notably for Celo:

  • End-to-end confirmation latency is significantly reduced, moving from minutes to near real-time. Blazar’s design enables rollups to reference blocks in their own logic without waiting for L1 confirmations.
  • System throughput and network stability are greatly improved through more efficient chunk distribution, optimized request routing, and horizontal scalability of DA nodes.
  • Support for decentralized dispersal is unlocked by eliminating DDoS attack surfaces inherent in the original push-based mode.

By integrating Blazar, Celo will be positioned to offer faster, more consistent performance for developers, especially those building high-throughput applications, while continuing to remain Ethereum aligned.

Our teams are working closely with the EigenDA team on implementation and will share more details on rollout as things progress.

Succinct: ZK-Enabled Fault Proofs

The cLabs team is excited to be exploring an integration with Succinct, a production-ready, zero-knowledge-powered fault proof system built in collaboration with OP Labs and Succinct. With Vitalik’s latest remarks around stage 2 requirements, we anticipate that every optimistic L2 will add zk-SNARK proofs to its security offering, and we’re excited that proving costs for machine code are now at a stage where this change is feasible for Celo without having to hand craft zk-SNARK circuits.

OP Succinct offers rollups two upgrade paths:

  • OP Succinct Lite: Adds ZK-powered fault proofs, used only in the event of a dispute
  • OP Succinct: Enables validity proofs for every transaction, removing the need for disputes entirely

Both options are compatible with the OP Stack and designed to improve finality, reduce complexity, and strengthen security.

Key benefits include:

  • Faster and configurable finality, with proofs generated only when disputes occur

  • ZK-powered resolution, reducing latency and complexity in the dispute process

  • Improved infrastructure security through bond-based incentives and proof verification

  • Support for alternative DA layers, aligning with Celo’s modular roadmap

Succinct’s architecture is built on Optimism’s Kona execution engine, Succinct’s high-performance zkVM (SP1), and the Succinct Prover Network.

To integrate with SP1, we would need to port native Celo features over from Go code in op-geth to Rust code in revm. While this is no small feat, it additionally brings us one step closer to having multiple client implementations, an important decentralization milestone that few chains achieve (and an important milestone for reaching Stage 2 down the line).

As with all major upgrades, any integration of OP Succinct would be subject to Celo Governance. The team is currently evaluating both configurations to determine the best path forward for Celo’s evolving security model and developer needs.

New Testnet Evaluation

With the Holesky testnet scheduled to sunset in Q3 2025, the cLabs team is evaluating the possibility of retiring the current Alfajores testnet and launching a new Celo L2 testnet on Sepolia.

A fresh L2 testnet would offer several long-term advantages:

  • Alignment with Ethereum: Periodically rotating testnets aligns Celo with Ethereum’s evolving testnet strategy and reduces friction for developers building across both ecosystems.

  • Simplified Architecture: Starting fresh eliminates legacy compatibility requirements, reduces hardware demands, and improves integration with Ethereum-native tooling and OP Stack infrastructure.

  • Faster Syncing: A clean slate means faster sync times for developers and node operators.

  • Reduced Complexity: Avoids the overhead of migrating state between multiple L1s (Celo L1, Holesky, Sepolia), simplifying client logic and reducing the risk of testnet-specific bugs.

While this would require protocols currently deployed on Alfajores to redeploy on the new testnet, we believe the benefits of a simpler, more reliable test environment outweigh the short-term disruption.

This new testnet would be designed to closely mirror Mainnet conditions while enabling easier experimentation and onboarding for developers. While timing is still being evaluated, the intention is to create a testnet that supports long-term scalability with minimal maintenance overhead.

Espresso: Exploring Fast, BFT-Backed Confirmations and Crosschain Interoperability

The cLabs engineering team has been actively exploring a potential integration with Espresso, a decentralized consensus layer purpose-built to deliver fast, secure confirmations for rollups. This integration would enhance Celo’s finality guarantees with near-instant, BFT-backed block confirmations, offering benefits similar to those of Celo’s original L1 consensus, but adapted for the L2 stack.

Espresso acts as a shared confirmation layer for L2s, improving both security and interoperability without compromising decentralization. Its consensus protocol ensures that only blocks confirmed by Espresso can be settled to Ethereum, effectively eliminating the risk of sequencer equivocation and protecting users from potential chain reorganizations.

Key benefits for Celo include:

  • Faster confirmations: Blocks can be confirmed in seconds (with sub-second latency on the horizon), eliminating long L1 settlement delays.

  • Enhanced security: Espresso confirmations are backed by a decentralized BFT consensus and will soon be secured by proof-of-stake.

  • Improved crosschain interoperability: L2s connected through Espresso gain reliable, near-real-time visibility into each other’s state, enabling fast, verifiable message passing and more efficient bridging.

  • Staker participation: Celo validators and token holders would help secure a global confirmation layer that complements Ethereum L1 and supports a more connected L2 ecosystem.

As with other major upgrades, any integration with Espresso would first require approval through Celo Governance. The team is in early conversations and actively evaluating alignment, architecture, and timing.

This potential collaboration represents an exciting opportunity to enhance both the performance and connectivity of Celo’s L2, while contributing to shared infrastructure that benefits the broader Ethereum rollup ecosystem.

Timeline

As Celo progresses through this next phase of growth, here’s a high-level view of upcoming milestones and when they’re expected to take shape:

  • Isthmus Hardfork: Q2 2025
  • EigenDA v2 (Blazar): End of Q2 / Start of Q3 2025
  • OP Succinct Lite: Q3 2025
  • New L2 Testnet (Sepolia): Q2 / Q3 2025
  • Espresso: Q3 2025

These dates are subject to change as development progresses and governance discussions unfold. We’ll continue to provide updates and opportunities for community input along the way.

Looking Ahead

Celo’s transition to an Ethereum Layer 2 was a major step, but it’s what comes next that will define the network’s long-term success. The milestones outlined above reflect a growing, maturing infrastructure designed to support developers, scale impact, and stay aligned with Ethereum’s modular future.

From core protocol upgrades like Isthmus, to foundational improvements in data availability and fault proofs, to the evaluation of a new testnet — each of these efforts is grounded in the belief that scalability, simplicity, and security must evolve together.

As these developments take shape, community input will be critical. Governance discussions, technical feedback, and experimentation on testnets will all play a role in shaping what comes next for Celo.

We’ll continue sharing updates as work progresses, and invite builders, contributors, and ecosystem partners to help chart this next chapter together.

The cLabs team

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