Ethereum Layer-2 Network Starknet Back Online Following Outage

In brief

• A block issue on Starknet mainnet was identified early Monday morning.
• The issue led to a pause of Starknet mainnet and an overall outage that lasted more than 4 hours.
• It is the second hours-long outage for the Ethereum scaling network in the last few months.

Ethereum layer-2 scaling network Starknet is back online after suffering a block production issue that led to more than four hours of downtime early Monday.  The first report of slow block production took place just before 5:00 am ET, according to the network’s status page. Around that time, the network’s mainnet block production was halted as developers investigated the issue.  “Starknet mainnet block production is temporarily paused while we investigate a proving error observed on a transaction,” a message shared in the network’s Telegram community read. “Out of caution we halted sequencing while we verify chain safety and state consistency. Transactions will not be processed during this period. We will share updates as we learn more.” 

According to another message in the Starknet Telegram around 7:00 am ET, a bug was identified and the team began working on additional testing, validation, and downstream impact assessment.  Ultimately, the blockchain was reverted to block 5187263, and around 9:00 am ET, the incident was resolved and the network resumed operational status.  “Starknet is back online and fully operational. Transactions submitted between 9:24 am and 9:42 am UTC may not have been processed properly,” the network posted on X. “A retrospective, including full timeline, root causes, and long-term prevention measures will follow.”

Starknet is back online and fully operational. Transactions submitted between 9:24 am and 9:42 am UTC may not have been processed properly. A retrospective, including full timeline, root causes, and long-term prevention measures will follow.

— Starknet (BTCFi arc) 🥷 (@Starknet) January 5, 2026

Additional details about the outage have not yet been revealed. A representative for the network pointed _Decrypt _to the network’s post on X Monday’s downtime marks the second operational outage for the layer-2 network in the last few months. Following the network’s Grinta upgrade in September, Starknet experienced more than five hours of downtime and required two chain reorganizations, which reverted approximately 80 minutes of transactions. Though primarily known as an Ethereum scaling network, Starknet added Bitcoin staking to its feature set in September, allowing users to stake the top crypto asset by market cap natively while earning STRK—its native token—in rewards.  The price of STRK was not significantly impacted by the downtime, showing a less than 1% dip over the last 24 hours to a recent price of $0.090, still up about 11% on the week. Ethereum (ETH), meanwhile, is up about 2% on the day to $3,192, rising nearly 9% in the last seven days.