Starknet Suffers Second Major Outage in Two Months, Raising Reliability Concerns

Ethereum's Layer 2 scaling solution, Starknet, experienced a significant network outage on September 2, 2025, halting on-chain transactions for nearly three hours. This marks the second major disruption for the network in just two months, sparking concerns about its reliability and stability within the rapidly growing Ethereum ecosystem.

Key Takeaways

• Starknet's network went offline early September 2, disrupting transactions.

• The outage was attributed to a sequencer failure related to "Cairo0" code incompatibility.

• Block production resumed, and most RPC providers are operational after a chain reorganization.

• This is Starknet's second major outage in two months, impacting its reputation for reliability.

Outage Details and Recovery

The outage, which began in the early hours of September 2, was caused by the Starknet sequencer, responsible for ordering transactions, failing to recognize the "Cairo0" code. This led to a halt in block production and a significant slowdown in transaction processing. Developers committed a chain reorganization from block number 1,960,612, affecting approximately one hour of activity. Transactions submitted between 2:23 a.m. and 4:36 a.m. UTC were not processed and will need to be resubmitted by users.

Starknet's team confirmed that the network was back online and fully operational within hours. Most RPC providers were reported to be back up and running, with remaining providers expected to upgrade shortly. A detailed retrospective, including the root cause and prevention measures, is anticipated.

Reliability Concerns and Competitive Landscape

This incident follows a previous, shorter outage on July 18, 2025, raising questions about Starknet's operational robustness. As the seventh-largest Layer 2 network with a Total Value Locked (TVL) of $548 million, Starknet's stability is crucial for its adoption and the broader Ethereum scaling narrative. The repeated failures could lead users and developers to favor more consistently performing L2 solutions like Arbitrum and Optimism.

The Grinta Upgrade and Future Outlook

The recent outage occurred shortly after the rollout of Starknet's Grinta upgrade (v0.14.0), which aimed to enhance decentralization by introducing multiple sequencers and improving the fee market. While the upgrade's goals are aligned with Ethereum's vision for scalable infrastructure, the compatibility issues with legacy code highlight the challenges in transitioning to more decentralized models. Despite the setbacks, the team's rapid response and commitment to transparency are seen as positive signs. However, Starknet must demonstrate consistent uptime and resolve its architectural vulnerabilities to maintain user trust and compete effectively in the evolving L2 landscape.

Sources

• Ethereum Layer 2 Starknet resumes block production after network outage, The Block.

• Ethereum L2 Starknet suffers 2nd Mainnet Outage within 2 months, Cointelegraph.

• Ethereum Layer 2 Starknet Faces Second Major Outage and Recovery in a Day, CoinCentral.

• Starknet's Grinta Upgrade and Network Reliability: A Critical Juncture for Ethereum Layer 2 Growth, AInvest.