The Arbitrum team clarified that its network was not down yesterday, despite many users reporting issues with transaction processing. The problems were caused by the batch poster failing to post batches of transactions to the chain for about an hour, not a network outage.

Batch Poster Failure, Not Full Outage

According to Arbitrum CTO Harry Kalodner, the sequencer kept accepting and ordering transactions during the incident, but the batch poster stopped adding them to the chain in batches. This caused delays in finality without making the network unusable.

The batch poster hit an edge case in transaction rejection logic, preventing it from escalating fees to push through backlogged transactions. A complex gas refunder setup contributed to the problem.

Perception Versus Reality

Many users understandably thought Arbitrum was down as transactions seemed not to process. But the network itself stayed online throughout, maintaining basic functionality despite the batching failure.

Situations like this illustrate how complexities under the hood can create user-facing problems without obvious explanations. Better transparency from teams can help manage confusion.

Robustness Still a Work in Progress

While not a total outage, the incident shows Arbitrum's operations are not yet bulletproof. As adoption grows, even small hiccups can impact many users. Hardening infrastructure to minimize weaknesses remains an ongoing process.

Maintaining high uptime and performance will be critical as competition among Layer 2s heats up. Arbitrum continues working to improve reliability amidst rapid scaling.

What Can Arbitrum Do to Prevent Issues Like This in the Future?

Comprehensive end-to-end testing, failover redundancies, monitoring tools to quickly detect failures, automated escalations, and additional engineer training would all help minimize future batch poster incidents.

How Does This Event Impact Perception of Arbitrum's Reliability?

While not catastrophic, the situation reinforces that Arbitrum is still maturing compared to battle-tested chains like Ethereum. Most users will quickly move on, but some may hesitate before committing large sums to the network until uptime improves.

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