ZkSync era vs starknet transaction finality time compared

03 October 2026

ZkSync Era achieves soft finality in roughly 10 - 15 seconds and hard finality in about 24 hours, while Starknet reaches soft finality in 30 - 60 seconds and hard finality in roughly 12 - 18 hours. The practical difference matters most for applications that need fast confirmation before settlement, or for users withdrawing assets to Ethereum mainnet.

What transaction finality means on l2s

On a layer 2 network, "finality" has two meanings. Soft finality is when the sequencer accepts your transaction and the L2 state updates locally. Hard finality (also called settlement finality) occurs when the validity proof or fraud proof is verified on Ethereum mainnet, making the transaction irreversible with full L1 security.

Both ZkSync Era and Starknet are ZK rollups, meaning they use validity proofs (zero-knowledge proofs) to settle batches of transactions to Ethereum. This differs from optimistic rollups, which rely on a challenge window. The proof generation time, proof submission frequency, and Ethereum block times all influence finality.

Soft finality: sequencer confirmation

ZkSync Era

ZkSync Era’s sequencer accepts transactions and updates the local L2 state within seconds. The network aims to produce blocks roughly every 10 - 15 seconds. During periods of high demand, block times may extend slightly, but the sequencer processes transactions continuously. Users see a confirmed transaction on the L2 block explorer within that window.

Starknet

Starknet’s sequencer operates on a different cadence. Blocks are produced approximately every 30 - 60 seconds, though this varies with network load. The longer block interval means soft finality takes longer than on ZkSync Era. However, Starknet batches multiple blocks together before generating a proof, which affects the subsequent hard finality timeline.

Hard finality: proof submission and settlement

Both networks must generate a validity proof for each batch of blocks, submit that proof to Ethereum, and wait for L1 confirmation. This process determines hard finality.

ZkSync era proof cycle

ZkSync Era generates a validity proof for each batch (typically containing several blocks) using its custom prover. Proof generation time depends on batch size and computational resources, but the team reports typical proof times under an hour. Once submitted to Ethereum, the proof must be included in an L1 block, which adds 12 - 15 seconds per block plus potential waiting time. After the proof is accepted on L1, the batch is settled.

In practice, ZkSync Era’s total hard finality time is usually around 24 hours. This includes proof generation, submission, and L1 confirmation. The network does not enforce a fixed delay - the actual time can be shorter during low activity or longer if proof generation is queued.

Starknet Proof Cycle

Starknet uses the SHARP prover (Shared Prover) to aggregate proofs for multiple blocks into a single validity proof. This batching reduces per-transaction proof cost but extends the time before submission. Starknet submits proofs to Ethereum in batches that may contain dozens of blocks. Proof generation for a large batch can take several hours.

After submission, the proof must be verified on Ethereum. Starknet’s hard finality typically falls between 12 and 18 hours, though it can stretch to 24 hours during congestion. The batching approach makes Starknet’s hard finality more variable than ZkSync Era’s.

What the Difference Means in Practice

For most everyday transactions - trading on a DEX, transferring tokens, or interacting with dApps - soft finality is what matters. You can treat the transaction as confirmed once the sequencer accepts it. The 15-second difference between ZkSync Era and Starknet is noticeable but rarely critical.

Hard finality becomes relevant in two scenarios:

• Withdrawals to Ethereum mainnet: You must wait for hard finality before the bridge releases your funds on L1. With ZkSync Era, expect roughly 24 hours; with Starknet, roughly 12 - 18 hours.
• Institutional or high-value settlements: If you need irreversible confirmation for accounting or regulatory reasons, hard finality is the clock that matters. Starknet’s faster hard finality may be advantageous here.

Which Network to Choose Based on Finality

If your application requires the fastest possible soft confirmation - for example, a high-frequency trading platform or a real-time game - ZkSync Era’s 10 - 15 second blocks offer a smoother user experience. Starknet’s 30 - 60 second blocks are acceptable for most DeFi applications but may feel sluggish for time-sensitive interactions.

If you frequently move assets between L2 and L1, Starknet’s shorter hard finality reduces withdrawal waiting time by roughly 6 - 12 hours compared to ZkSync Era. However, both networks require at least half a day, so the difference may not be decisive if withdrawals are infrequent.

Neither network has a meaningful edge for typical L2-to-L2 transfers, since those rely on third-party bridges that have their own finality rules.

Other factors that affect finality

Network congestion can increase both soft and hard finality times. During peak usage, ZkSync Era’s sequencer may queue transactions, and Starknet’s block times may stretch. Proof generation resources are also shared across all users; a backlog in the prover can delay hard finality on either network.

Both teams continue to optimize their provers and submission schedules. The figures given here reflect typical behavior as of late 2025. For current average block times and proof submission intervals, check the respective network status pages or L2Beat.

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