Canonical bridge

ZKsync Portal

ZKsync Portal is the official app for moving funds between Ethereum and ZKsync Era. ZKsync proves its transactions to Ethereum with zero-knowledge proofs, so withdrawals do not need a week-long challenge period. They still wait for the proof plus a safety delay of at least 3 hours.

Official website

How it works

1To deposit, you send ETH or a token to the ZKsync bridge contracts on Ethereum. The same amount is credited to you on ZKsync, usually within minutes.
2To withdraw, you start on ZKsync. The batch with your withdrawal is proven on Ethereum and then waits out a delay of at least 3 hours.
3After that you claim the funds on Ethereum, paying Ethereum gas.

Trust model

You trust the ZKsync contracts on Ethereum and the validity proofs they check. ZKsync governance can upgrade the contracts, and the withdrawal delay gives time to react to a problem.

Strengths

Much faster official withdrawals than optimistic rollups such as Arbitrum or OP Mainnet.
Security rests on math proofs checked on Ethereum, not on a group of bridge validators.
No bridge fee beyond network gas.

Limitations

Withdrawals take hours, not seconds; a fast bridge is quicker for small amounts.
Only connects Ethereum and ZKsync.
You need ETH on Ethereum to claim a withdrawal.