WBTC input identity and handling
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 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.
zkSync Era destination 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.
BNB output identity and receiving
BNB is classified as a native asset for this route. BNB uses a network-specific contract asset on zkSync Era. The recorded zkSync Era representation uses 18 decimal places. Native BSC receipt can fund BNB gas, while externally bridged BNB arrives as a representation that needs the destination chain’s gas token.
Base source 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.
EVM-to-EVM execution boundary
Base and zkSync Era can use the same 0x address syntax, but they are separate networks with different chain identifiers, gas balances, token contracts, and transaction histories. The recorded settlement context includes ethereum, so L1 and L2 confirmation behavior should not be assumed identical.
Mistakes specific to WBTC Base to BNB zkSync Era
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. Native BSC receipt can fund BNB gas, while externally bridged BNB arrives as a representation that needs the destination chain’s gas token.