On June 11, Ethereum Foundation co-founder Vitalik Buterin commented on the current state of Ethereum Layer 2 (L2) projects, and more specifically Optimism’s OP Mainnet.

The image he embedded in his post on the social media platform X (formerly known as Twitter) shows a list of L2 scaling solutions for Ethereum, categorized by their stage of development and the type of rollup technology they use (ZK Rollup or Optimistic Rollup). Vitalik Buterin’s post suggests that “stage 1+” L2s are those with robust proof systems that provide strong security guarantees. He welcomes Optimism to this group and expresses his hope that more L2s, particularly those using Zero-Knowledge (ZK) proofs, will soon achieve this level of maturity.

Based on this image, there are currently no ZK-Rollups in stage 2, which is the stage Buterin is referring to when he mentions “proof systems that actually have teeth”. Only Optimistic Rollups like Fuel V1 and DeGate V1 have reached stage 2.

The image is a screenshot from L2BEAT, a website dedicated to tracking and comparing various Ethereum Layer 2 scaling solutions.

L2BEAT offers a detailed overview of different L2 projects, covering aspects such as technology, performance, security, and adoption metrics. Their categorization system is designed to help users grasp the diverse approaches to scaling Ethereum and to stay informed about the current status of each project.

Stage refers to the rollup stage based on its featured and maturity:

  • Stage 0 (“full training wheels”)
  • Stage 1 (“limited training wheels”)
  • Stage 2 (“No training wheels”)

Stage 0: Full Training Wheels

The “Stage 0” designation signifies that the Layer 2 solution is in its initial development phase, marked by several key limitations:

  1. Incomplete Proof System: The mechanism for verifying transactions, known as the proof system, is still being developed.
  2. Withdrawal Censorship: There is a risk that users’ withdrawals can be restricted by centralized operators who have permission to control this process.
  3. Centralized Upgrades: Updates managed by centralized actors, as opposed to a more decentralized Security Council, provide users with less than 7 days to exit in the event of operator issues or censorship.

Stage 1: Limited Training Wheels

The “Stage 1” status indicates some progression from Stage 0 but highlights areas needing improvement to achieve further decentralization and user assurance:

  1. Restricted Fraud Proofs: Only pre-approved (whitelisted) actors can submit fraud proofs, which limits openness and decentralization.
  2. Short Upgrade Notices: Upgrades that are not related to on-chain provable bugs give users less than 30 days to exit, limiting their response time.
  3. Broad Security Council Actions: The Security Council’s actions are not strictly limited to on-chain provable bugs, suggesting a need for clearer governance rules.

L2BEAT points out that these stages do not reflect the security of the rollup itself.