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Available on Testnet today. Testnet finality delays are intentionally short. Mainnet values are published before Mainnet launch. All operational timings, confirmation phases, and roadmap values are provided “AS IS” for technical reference and do not constitute performance guarantees or SLAs.
A transaction passes through three states: soft confirmation, safe, and finalized. Only finalization makes it irreversible under standard protocol execution. Only withdrawals to Ethereum wait for the dispute-resolution period. A normal transaction on Whitechain, such as a send, a swap, or a contract call, is included in about one second and reaches finality in under an hour on Testnet.

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Confirmation stages

The one-second and 13-minute figures are protocol timings. Block production runs at one second while the sequencer is live, and the 13-minute figure is Ethereum’s finality interval, so it follows L1. The safe delay depends on how often batches are posted, up to about 30 minutes on Testnet. A soft confirmation is the weakest of the three stages: it carries the sequencer’s word and nothing more.

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The transaction lifecycle

  1. Send you submit the transaction and the sequencer receives it.
  2. Soft confirmation the sequencer orders the transaction and includes it in an L2 block, about once per second. Your wallet shows it as complete, but the guarantee is only the sequencer’s word. Because one sequencer orders every transaction, a soft confirmation can still be reordered or dropped before the batch reaches Ethereum. Treat it as fast feedback, not a final receipt. Whitechain assumes no liability for losses arising from reliance on unbatched soft confirmations.
  3. Safe the sequencer groups transactions into batches, compresses them, and the op-batcher posts them to Ethereum as blobs (EIP-4844). Once that batch is confirmed on Ethereum, your block is safe. Separately, the op-proposer publishes the L2 state root to Ethereum through the DisputeGameFactory contract.
  4. Finalized when the Ethereum block that carries your batch reaches Ethereum finality, about 13 minutes later, your L2 block becomes finalized. From that point the L2 state derives from finalized Ethereum data and cannot be reversed. Finality guarantees depend strictly on underlying Ethereum consensus mechanics.
An Ethereum reorg does not roll back a finalized L2 block. A shallow reorg can move the safe head: the node re-derives from the canonical Ethereum chain and the affected batch is re-posted. Blocks that reached finality are protected the same way finalized Ethereum blocks are. Whitechain is in Testnet, so historical reorg rates are not yet published. Expected figures are added with Mainnet.

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Flashblocks

Flashblocks are not enabled on Whitechain Sepolia. The rollout is prepared and staged per sequencer, and no date is set. Flashblocks rollout schedules and preconfirmation features are forward-looking and subject to technical modification or delays. Once enabled, the sequencer streams partial blocks ahead of each full one-second L2 block, powered by Flashbots rollup-boost, which runs a block builder alongside the sequencer. Each partial block is a preconfirmation: it says your transaction is included and ordered. It carries the same trust as a soft confirmation, the sequencer’s word, and is not safe or finalized until its batch reaches Ethereum. The interval is published here once it is measured on a live stream. The stream is separate from the public RPC and stays that way, so there is no Flashblocks endpoint to connect to today; see what a node does not provide. Build against the three confirmation stages above. The rollout does not change them.

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Withdrawing to Ethereum

Finality makes your L2 state irreversible. Moving assets back to Ethereum takes longer, because a withdrawal must also clear a dispute-resolution period. On Testnet a full withdrawal takes about an hour. Whitechain Mainnet is not live, so its dispute period is not published. On OP Mainnet the equivalent period is a minimum of 7 days, set in the L1 contracts. The dispute period is enforced by those contracts and cannot be shortened, waived, or overridden by the operator or any third party. Deposits run the other way in about 2 minutes. Both figures move with Ethereum block times and L1 congestion. See the canonical bridge guide for the steps and exact timing parameters.

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What keeps your funds safe

A designated infrastructure operator runs the sequencer today, so liveness, whether new blocks are produced, depends on it. Safety rests on Ethereum, but not unconditionally. The mechanisms below hold your funds as long as transaction data stays on Ethereum and an honest challenger disputes any invalid state root. Protocol mechanics do not guarantee absolute protection against unforeseen smart contract vulnerabilities or zero-day exploits.

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Data availability

Every transaction’s data is posted to Ethereum. Anyone can download it and recompute the L2 state, so the sequencer cannot hide or alter a transaction.

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Fault proofs

A proposed state root can be disputed on Ethereum through an on-chain game. The game replays the disputed step in Cannon, a MIPS virtual machine, and the side proven wrong loses its bond. Today that game is permissioned, so only the configured challenger can dispute a root. The design moves toward permissionless challenging, where anyone can take part. A Guardian role can also pause withdrawals or blacklist a game that resolves incorrectly. Users acknowledge that emergency Guardian interventions, permissioned roles, or protocol pauses may restrict or halt transaction execution and withdrawals without prior notice.

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Censorship resistance

If the sequencer refuses your transaction, you can submit it through the OptimismPortal contract on Ethereum. The protocol must then include it within the sequencing window, about 12 hours, or the chain is invalid.