WBTC source representation
Wrapped Bitcoin is classified as a wrapped asset for this route. WBTC uses a wrapped contract asset on Base. The Base side is contract-tracked rather than a native gas balance. WBTC leaves through a custodial wrapper contract with token approval and source-chain gas; no native Bitcoin UTXO is spent by that transfer.
Base to zkSync Era L2 handoff
This route crosses two L2 execution environments. Base settles to ethereum, while zkSync Era settles to ethereum; each side keeps its own gas balance, token contracts, transaction hash, and settlement progress.
WBTC destination representation
Wrapped Bitcoin is classified as a wrapped asset for this route. WBTC uses a wrapped contract asset on zkSync Era. The recorded zkSync Era representation uses 8 decimal places. WBTC arrives as a wrapper-contract token and must not be sent onward to a native Bitcoin address without an explicit unwrap or bridge path.
zkSync Era receipt-side execution
zkSync Era is a L2 EVM network in the Ethereum ecosystem. ETH pays destination-side network gas on zkSync Era. EVM 0x account address A zkSync Era receipt belongs to EraVM account state and uses ETH for later fees; proof settlement to Ethereum remains distinct from L2 delivery.
Base deposit-side execution
Base is a L2 EVM network in the Ethereum ecosystem. ETH pays source-side network gas on Base. EVM 0x account address A Base source transaction is sequenced on the OP Stack rollup and later settles to Ethereum; Base ETH and Base token approvals remain on the L2 ledger.
WBTC unwrap or exchange input check
WBTC is a custodial tokenized Bitcoin representation on smart-contract networks. Its transfers use token contracts and approvals rather than native Bitcoin inputs and outputs. On this route WBTC is the source token on Base. Its token balance, approvals, and contract transfer behavior are separate from the native coin used for network gas.
Base to zkSync Era bridge mistakes
Route-specific mistakes include sending on a network other than Base; using a destination that is not valid for zkSync Era; running out of ETH before the source transaction is submitted; treating a wrapped token as the native gas asset. A Base source transaction is sequenced on the OP Stack rollup and later settles to Ethereum; Base ETH and Base token approvals remain on the L2 ledger. WBTC leaves through a custodial wrapper contract with token approval and source-chain gas; no native Bitcoin UTXO is spent by that transfer. A zkSync Era receipt belongs to EraVM account state and uses ETH for later fees; proof settlement to Ethereum remains distinct from L2 delivery. WBTC arrives as a wrapper-contract token and must not be sent onward to a native Bitcoin address without an explicit unwrap or bridge path.