Optimism

Optimism is a layer 2 project that runs OP Mainnet, an optimistic rollup on Ethereum, and develops the OP Stack, open-source software that other teams use to launch their own rollups. Transactions on OP Mainnet are executed off Ethereum and posted back to it, and are assumed valid unless challenged with a fault proof. The software is built mainly by OP Labs, and the network is governed by the Optimism Collective through the OP token.¹²³

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Plasma Group and founding

Optimism grew out of Plasma Group, a non-profit research organisation working on Ethereum scaling. CoinDesk reports that Jinglan Wang and Karl Floersch, a former Ethereum Foundation researcher, set it up, and that the group moved from Plasma designs to optimistic rollups as demand for cheap transactions grew. It lists the founding team as Wang, Ben Jones, Floersch, Mark Tyneway, Kelvin Fichter and Kevin Ho.⁴ Plasma Group shut down on its first anniversary and donated its remaining funds to Gitcoin. Its members founded Optimism, a for-profit company later known as Optimism PBC, in December 2019, with Wang as chief executive.⁵³

Funding

In January 2020 the new company raised a US$3.5 million seed round from Paradigm and IDEO CoLab Ventures.⁵ Andreessen Horowitz (a16z) led a US$25 million Series A, announced on 23 February 2021. a16z's post named "Jing, Karl, Ben and the rest of the team" and traced the work to "the team's research at Plasma".⁶⁷ On 17 March 2022 Optimism announced a US$150 million Series B co-led by Paradigm and a16z at a US$1.65 billion valuation.⁸⁹

Soft launch and the OVM

Optimism opened a limited mainnet, then called Optimistic Ethereum, on 15 January 2021, with Synthetix as its first application. The team said it would hold upgrade keys for at least the first six months and warned users to expect outages and bugs.¹⁰¹¹ Contract deployment was restricted to an allowlist of approved projects.¹²

The first design, the Optimistic Virtual Machine (OVM), was not a copy of the EVM. Contracts were compiled with a modified Solidity compiler that replaced some opcodes with calls to OVM equivalents and banned others, so not all Ethereum contracts could run unchanged.¹²

Regenesis and EVM equivalence

On 11 November 2021 Optimism carried out its final "regenesis", restarting the chain from a new genesis state with an upgrade that made it EVM equivalent. Transactions from before that date are not part of the current chain.¹³¹⁴ The upgrade also removed the OVM's fraud proof system; OP Mainnet would not have working fault proofs again until June 2024.¹⁵ On 16 December 2021 Optimism removed its allowlist, letting anyone deploy contracts.¹⁶

OP token and the Collective

On 26 April 2022 Optimism announced the Optimism Collective, a governance structure with two co-equal houses. Optimism PBC was renamed OP Labs PBC, and a new Optimism Foundation, led by Wang and Jones, was formed to steward the Collective.³ The OP token launched on 31 May 2022 with an airdrop of about 214 million OP, 5% of the initial supply.¹⁷ The initial allocation was:¹⁸

Further airdrops followed, starting with 11.7 million OP to more than 300,000 addresses on 9 February 2023.¹⁹ In August 2026 governance approved a Foundation proposal to re-designate the unspent 546.9 million OP of the user airdrop allocation as a "Strategic Ecosystem Fund".²⁰

Retroactive Public Goods Funding

Retroactive Public Goods Funding (later Retro Funding) rewards projects after they have shown impact; the Collective's founding pact rests on what Optimism calls "the axiom of impact=profit".³ The first round allocated US$1 million. Later rounds allocated 10 million OP (round 2), 30 million OP to 501 recipients (round 3, announced 11 January 2024), and between about 2 and 10 million OP each in rounds 4 to 7.²¹²²²³ In January 2026 the Foundation paused Retro Funding for at least a year; by August 2026 about 81 million OP of the 859 million allocated had been committed.²⁴²⁵

Bedrock and the OP Stack

On 17 October 2022 Optimism introduced the OP Stack, a modular framework for building rollups, and described a future "Superchain" of interconnected chains sharing it. Bedrock, a rewrite of the OP Mainnet codebase, was to be its flagship release; Optimism says it is about a hundredth the size of the original OVM code.¹ OP Mainnet migrated to Bedrock on 6 June 2023, with several hours of planned downtime. The Foundation stated the upgrade would lower fees and make the bridge more secure.²⁶²⁷

Later network upgrades included Ecotone (14 March 2024), which moved data posting to Ethereum blobs; Granite (11 September 2024); Holocene (9 January 2025); Isthmus (9 May 2025); Jovian (2 December 2025); and Karst (8 July 2026).²⁷

Base and the Superchain

Coinbase built its Base network on the OP Stack and launched it in August 2023. Base agreed to send the Collective the greater of 2.5% of its sequencer revenue or 15% of its net sequencer revenue, and could earn up to about 118 million OP over six years, with its voting power capped at 9% of votable supply.²⁸ The "Law of Chains", published in July 2023, set out principles for chains that opt into Superchain governance.²⁹

Other chains that joined the Superchain include Unichain, World Chain, Soneium and Ink.³⁰ Ronin announced a migration to an OP Stack layer 2 in 2025, and OKX moved its X Layer network from Polygon CDK to the OP Stack.³¹³² Optimism states that 54 mainnet chains were built on the OP Stack as of October 2026.³³

Fault proofs and decentralisation

Permissionless fault proofs went live on OP Mainnet on 10 June 2024, allowing anyone to propose and challenge state claims used to prove withdrawals. L2Beat then classed OP Mainnet as Stage 1.³⁴¹⁵ On 16 August 2024 fault proofs were disabled as a precaution after a bug was found, and OP Mainnet fell back to permissioned proposals; L2Beat records the suspension as lasting 26 days, ending with the Granite upgrade in September 2024.¹⁵²⁷

The Security Council began signing OP Mainnet upgrades on 9 February 2024, initially in a 2-of-2 multisig with the Optimism Foundation.³⁵ Optimism stated in September 2026 that the council has 13 voting members and a 75% signing threshold.³⁶

Base's departure and restructuring (2025–2026)

In November 2025 Wang wrote that the team "did too much and focused too little", and said the project had cut staff, unified execution under one entity and would focus on the OP Stack and enterprise customers.³⁷ On 29 January 2026 Optimism launched OP Enterprise, a set of infrastructure and support tiers, including fully managed hosting by OP Labs, for companies running OP Stack chains.³⁸

On 8 January 2026 the Foundation proposed spending 50% of incoming Superchain revenue on monthly OP purchases for a year, with the tokens returned to the treasury.³⁹ Token holders approved it on 28 January 2026 with about 84% support; purchases began in February through over-the-counter swaps.⁴⁰ The Foundation reported buying more than 9 million OP by August 2026.²⁵

On 18 February 2026 Base announced it would move from the OP Stack to its own codebase, base/base, and said it planned to switch from optimistic proofs to TEE and ZK proofs.⁴¹ The Foundation confirmed that Base's revenue share would not continue and that Base would not receive the unvested part of its OP grant; Base remained a customer of OP Enterprise.⁴²³⁰ DL News reported that Base had contributed 8,387 ETH, 41% of the Collective's lifetime revenue, and 90% of its revenue in January 2026.³⁰ On 12 March 2026 OP Labs laid off 20 employees, about a fifth of its staff; Wang said the cut was "not about finances".⁴³

Interoperability

Optimism's plan for the Superchain includes native message passing between OP Stack chains. Interop ships in the Lagoon network upgrade, which as of October 2026 was still in development. Optimism's documentation targets a first two-chain interop set of OP Sepolia and Unichain Sepolia on 3 December 2026, followed by OP Mainnet and Unichain subject to governance approval; it gives both 15 December 2026 and 11 January 2027 as the mainnet date.⁴⁴⁴⁵

TechnologyReport an error

A single sequencer orders OP Mainnet transactions and posts them to Ethereum, using blobs since March 2024. A Foundation multisig can change the sequencer through the SystemConfig contract. Users can force transactions through Ethereum if the sequencer censors them, with a delay of up to 12 hours.¹⁵

Since Bedrock, the OP Stack separates a consensus-layer client (op-node) from an execution client (such as op-reth), following the split Ethereum adopted for The Merge.¹⁴⁵

Withdrawals to Ethereum must be proven against a state proposal submitted through the DisputeGameFactory contract. Anyone can submit or challenge a proposal. Disputes are resolved by an interactive bisection game that ends in a one-step proof of a single MIPS instruction on Ethereum; Cannon is the fault proof virtual machine used for this. The system is designed to support further proof systems, including zero-knowledge proofs.²⁴⁶³⁴ L2Beat lists a challenge period of 3.5 days followed by a 3.5-day execution delay.¹⁵

L2Beat classes OP Mainnet as Stage 1, not Stage 2, because the Security Council can act outside provable bugs and because upgrades give users less than 30 days to exit. Emergency upgrades can be executed immediately.¹⁵

GovernanceReport an error

The Token House votes with OP, directly or by delegation, on protocol upgrades, treasury grants and other proposals. Votes require a quorum of 30% of votable OP supply.⁴⁷ The Citizens' House is a one-person, one-vote body whose members hold non-transferable badges; its first version launched in December 2022 to vote on Retro Funding.³²² The upgrade process in Optimism's documentation includes a veto period in which the Citizens' House can block upgrades approved by the Token House.²⁷

The Optimism Foundation is a Cayman Islands foundation company governed by a board of directors and a supervisor. Governance can vote to remove directors and block changes to its documents that reduce token holders' rights.⁴⁷ In 2026 the Foundation said it intended to turn the Collective "from experiment to organization", including a possible new legal entity such as a DUNA.²⁴

Incidents and controversiesReport an error

• Wintermute loss (June 2022). The Foundation sent 20 million OP to an address supplied by the market maker Wintermute, which was Wintermute's Ethereum address and had not been deployed on Optimism. Wintermute took responsibility. An unknown attacker gained control of the address on Optimism and took the tokens, then sold 1 million and sent 1 million to Vitalik Buterin's address. Wintermute bought back the tokens sold. On 10 June 2022 the attacker returned 17 million OP.⁴⁸⁴⁹
• Airdrop launch (May 2022). Some users claimed OP early by calling the contract while the team was still testing, and some users reported being shown as ineligible after earlier being eligible.⁵⁰
• ETH duplication bug (2022). On 2 February 2022 the researcher Jay Freeman (saurik) reported a bug in Optimism's Geth fork in which SELFDESTRUCT could duplicate ETH. Optimism said it had not been exploited, apart from one accidental trigger by an Etherscan employee. Freeman received a bounty of US$2,000,042, and forks of the code were also patched.⁵¹⁵²
• Fault proof suspension (August 2024). Fault proofs were disabled for 26 days after a bug was found, as described above.¹⁵
• Lost early data. OP Labs states that data directories holding event logs and transaction status for January to July 2021 were deleted in error in August 2023. Balances were unaffected.⁵³
• Fraud proofs removed (2021–2024). From the November 2021 regenesis to June 2024, OP Mainnet ran without working fault proofs.¹⁵
• Token grants. CoinDesk reported that competitors had noted Optimism's use of large OP grants to win adoption; the Foundation said chains decide whether to disclose their grant amounts, and several did not.⁴
• Base revenue and OP Enterprise. After Base's departure, the delegate GFXlabs argued that Base was now paying OP Labs while token holders received nothing. The Foundation said OP Enterprise revenue goes to the Foundation and that it was exploring using it for buybacks.⁴²

TimelineReport an error

See alsoReport an error

• Ethereum
• Arbitrum, a competing optimistic rollup
• Base, built on the OP Stack until 2026
• Uniswap, whose Unichain is built on the OP Stack

ReferencesReport an error