Orca Crypto
Technology term

Optimistic rollup

A rollup that assumes transactions are valid unless someone proves otherwise.

All terms
All termsAddressBlockBlock timeBlockchainConfirmationGasGweiHashMempoolNodePrivate keyPublic keySeed phraseTransactionWalletAll time high (ATH)Bear marketBull marketCandlestickCapitulationChart patternsDollar cost averaging (DCA)Funding rateLeverageLimit orderLiquidationLiquidityMarket capMarket orderOrder bookPosition sizingRisk managementSlippageSpreadSupport and resistanceTrendVolatilityVolumeWhaleAMMBridgeCEXDAODeFiDepegDEXFlash loanGovernance tokenImpermanent lossLiquidity poolLP tokenOraclePerpetual (perp)RestakingRWAStablecoinTVLWrapped tokenYield farmingAirdropAlphaApe inBagholderDegenDiamond handsFloor priceFOMOFUDGMHODLMaxiMeme coinMoonNFTNGMINormiePaper handsPFPRektShillSnapshotWAGMIAddress poisoningCold storageCustodyDue diligence (DYOR)Dusting attackExit scamFront runningHardware walletHoneypotHot walletMEVMultisigPhishingPump and dumpRug pullSandwich attackSelf custodySIM swapToken approvalTwo factor authenticationWallet drainerWash tradingAccount abstractionAppchainBlock explorerCirculating and total supplyConsensusData availabilityEVMFaucetFinalityForkFully diluted valuation (FDV)Gas warHalvingLayer 1Layer 2Layer 3MainnetMiningName serviceOptimistic rollupProof of stakeProof of workRollupShardingSidechainSlashingSmart contractStakingTestnetToken standardTokenomicsValidatorZero knowledge proofZK rollupArweave and the permawebComposabilityCross chain messagingdAppDecentralized identity (DID)DePINGameFi and play to earnIndexerInteroperabilityIPFSOnchain and offchainSession keysSmart accountSocialFiSoulbound tokenSybil resistanceToken gatingWeb2 vs Web3Web3
Updated 2026-08-303 min readDefinition
Definition

A rollup that assumes transactions are valid unless someone proves otherwise.

Optimistic rollups post results and open a challenge window, typically seven days. Anyone can submit a fraud proof during that period to reverse an invalid batch.

The tradeoff is withdrawal time. Moving funds back to layer 1 through the official route means waiting out that window, though bridges offer instant exits for a fee.

In practice

Arbitrum, Base, OP Mainnet and Blast are all optimistic rollups.

Where to go next

More technology terms

Back to the full encyclopedia

Want this explained out loud?

Some of these land faster in conversation than in writing. Sessions are one to one and you can ask anything, including the things that feel too obvious to ask.