Hyperliquid posts incident report for Arbitrum bridge failure citing 'extremely rare edge case'

Hyperliquid, one of the most popular decentralized perpetual exchanges, has posted an incident report explaining why its bridge went down on Monday. 

According to pseudonymous developer iliensinc, there was an “extremely rare edge case” where multiple RPCs (short for Remote Procedure Calls, the protocols used to connect users and applications to blockchain nodes) were served incorrect data.

Hyperliquid's bridge to Arbitrum, the largest Ethereum Layer 2, was down for about four hours after bridge validators voted for an emergency lock. There was a second lockup period that lasted for a few minutes about an hour after it was reopened.

“The Arbitrum bridge was locked earlier today due to an automatic monitoring process run by L1 [in this case, Hyperliquid] validators. The process relies on many major Arbitrum RPCs and ensures that the L1 and Arbitrum state are synced,” iliensinc wrote on Discord.

According to Hyperliquid’s documentation, only two validators are required to vote to lockdown the protocol during similar emergencies, though all four operating validators voted to temporarily close the bridge. “This seems like a good thing,” Theo Network’s Abhi Pingle said on X.

Iliensinc noted the locking mechanism is meant “as a last resort to prevent exploits” and designed to preserve user funds, which would be a “far worse outcome than occasional downtime.”

“Improvements are being made to the monitoring process to prevent the same false positive from triggering in the future. All user funds are safe,” they added.

It appears this is the first time Hyperliquid, a protocol with nearly $700 million total value locked, experienced downtime since going live since launching last year.

Like many newer DeFi projects, Hyperliquid bootstrapped growth by running points programs that would reward users with tokens.

Editor's note (12:33 p.m. ET): An earlier version of this story misstated Hyperledger as the exchange.