WETH input identity and handling
WETH is classified as a wrapped asset for this route. WETH uses a wrapped contract asset on Base. The recorded Base representation uses 18 decimal places. WETH leaves through a wrapper contract and needs native chain gas. A WETH token balance cannot pay the gas required to submit its own transfer.
Base to Optimism L2 handoff
This route crosses two L2 execution environments. Base settles to ethereum, while Optimism settles to ethereum; each side keeps its own gas balance, token contracts, transaction hash, and settlement progress.
WETH unwrap or exchange input check
WETH is a contract wrapper for ETH. It can be transferred as a token but cannot replace the native gas balance required by the network. On this route WETH is the source token on Base. Its token balance, approvals, and contract transfer behavior are separate from the native coin used for network gas.
Optimism destination execution
Optimism is a L2 EVM network in the Ethereum ecosystem. ETH pays destination-side network gas on Optimism. EVM 0x account address An OP Mainnet receipt belongs to the OP Stack L2 and needs ETH on that network for later activity; it is not an Ethereum L1 balance.
WBTC output identity and receiving
Wrapped Bitcoin is classified as a wrapped asset for this route. WBTC uses a wrapped contract asset on Optimism. The recorded Optimism 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.
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 Optimism 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 WETH Base to WBTC Optimism
Route-specific mistakes include sending on a network other than Base; using a destination that is not valid for Optimism; 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. WETH leaves through a wrapper contract and needs native chain gas. A WETH token balance cannot pay the gas required to submit its own transfer. An OP Mainnet receipt belongs to the OP Stack L2 and needs ETH on that network for later activity; it is not an Ethereum L1 balance. 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.