Optimism Finally Gets Its Mission-Critical 'Fault Proofs'

For years, Optimism was missing a core feature at the heart of its design: "Fault proofs." On Monday, that tech is finally here.

Layer-2 blockchain Optimism is finally rolling out a critical piece of technology to its mainnet on Monday, putting an end to years of lagging behind its competitors and enduring criticism over the safety of its network.

Optimism is best known for helping Ethereum users transact quickly and for lower fees, serving as the foundation tech for some of the biggest names in blockchain, including the Coinbase exchange's Base blockchain and Worldcoin's World Chain – from OpenAI founder Sam Altman.

But there's been a problem. All of the blockchains that use Optimism's technology are built according to a core underlying premise: They "borrow" Ethereum's security apparatus. In reality, however, that wasn't the case. Until now.

Optimism has been missing a core feature at the heart of its security design: "Fault proofs." On Monday, that long-promised tech is finally coming to Optimism's mainnet.

Optimism Derives Its Name From Its 'Optimistic' Proof System

Optimism derives its name from its "optimistic" proof system, and it launched a version of the tech when it first released in 2021 before quickly scrapping it after finding issues.

“We literally deleted the entire system essentially, re-architected it, and rewrote the entire thing,” Karl Floersch, the CEO of OP Labs, said in an interview with CoinDesk. “That was brutal, but absolutely the correct decision.”

The Optimism team previously shared in March that it was testing its fault proofs system on their Sepolia testnet. Since then, they had an audit conducted by blockchain security firm Sherlock, and found a few bugs that they were able to patch out.

“So we fixed everything that we did find, and we got a lot of confidence in the actual implementation being ready for prime time,” Floersch said.

Starting this week, the network will again rely on a fault-proof system to power withdrawals, but it will still retain "training wheels" meant to ensure that things run smoothly. The Security Council will remain intact and can intervene in the event that the fault-proof system goes down. This combination of the two entities is what Optimism is calling “Stage 1 decentralization.”

The goal is to eventually reach Stage 2 decentralization, where the network will not have to rely on the Security Council at all.

“Stage 2 is a multiple fault proof system, sufficient such that it is possible to run the system in some ways, like on autopilot. There's no ability for the Security Council to intervene at the last moment,” Floersch said.

Floersch added that the team is hard at work to reach its Stage 2 goals, but he didn't give a timeline for when that ultimate vision would be reached.

With fault proofs finally shipping to Optimism's mainnet, other chains that use Optimism's OP Stack will gain access to the tech as well. (According to DefiLlama, two blockchains that use Optimism's OP Stack, Blast and Base, currently surpass Optimism's mainnet in terms of total value locked.)

“We're going to start with OP mainnet for this upgrade, it's a decently large upgrade,” Floersch told CoinDesk. “However, it should not be too long” for Coinbase's Base chain to implement the fault proof system, too, Floersch added.