What caused Base blockchain’s 33-minute network outage?

Base, Coinbase’s Ethereum layer-2 blockchain, experienced a 33-minute network outage on Aug. 5 after a faulty sequencer transition halted block production.

A bug in Conductor, an OP (OP) Stack component that oversees Base’s high-availability sequencer cluster, was the root cause of the incident. According to a postmortem released by the Base team, the sequencer handoff mechanism chose a backup node that wasn’t fully provisioned, which caused a halt in transaction processing.

Sequencer handoff fails during on-chain congestion

The disruption began at 6:07 am UTC when the primary sequencer lagged due to a spike in on-chain activity. Conductor, designed to maintain uptime by rotating sequencers, elected a new node mid-provisioning.

Lacking full Conductor functionality, the replacement couldn’t initiate another handoff, leaving the chain unable to produce blocks. At 6:12 am, Base formally declared the incident and began mitigation steps.

By 6:40 am UTC, the team had manually transferred leadership to a healthy sequencer and resumed block production. No funds were lost during the event. Protocols like Aave (AAVE) and Moonwell avoided liquidation errors thanks to Chainlink’s (LINK) Sequencer Uptime Feed circuit breakers.

The team paused Conductor, manually coordinated a safe transition, and evaluated reorgarnization risks. The outage, which impacted Flashblocks, withdrawals, and deposits, lasted 33 minutes in total.

Infrastructure fixes in progress

Base plans to upgrade its infrastructure to ensure that all sequencers added to the cluster can execute handoffs in order to stop recurrence. Additional testing and monitoring enhancements will also be rolled out in the coming days.

The outage is Base’s first major downtime since September 2023, when the network was down for 43 minutes shortly after its public launch. The incident has renewed scrutiny of centralized sequencer architectures, especially as Base now secures over $4.1 billion in total value locked.

Base joins a growing list of recent L2 disruptions, including Hyperliquid’s (HYPE) July 29 API outage caused by a traffic spike, and TON’s 40-minute halt on June 1 during the DOGS token launch.