Metis Bridge

Metis Bridge is the canonical message-passing route between Ethereum (chain ID 1) and Metis Andromeda (chain ID 1088). A deposit locks the asset in the L1 Standard Bridge contract — proxy 0x3980c9ed79d2c191A89E02Fa3529C60eD6e9c04b — then a cross-domain message credits the same address on Andromeda. This is a bridge rather than a swap: there is no counterparty pool, and the same asset moves from one chain to the other. The Metis Andromeda documentation lists METIS, ETH, WBTC, USDC, USDT, and DAI among canonical-route assets; the interface controls live availability.

Third-party bridges are separate products that use liquidity-based transfers to cover additional chains or provide faster movement. Their contracts, fees, and trust models are distinct from the canonical route. Use the canonical route for standard Ethereum-to-Metis movement of a supported major asset; consider a third-party route when you need a faster exit or a chain the canonical bridge does not serve.

Bridging works by having your self-custody EVM wallet authorize a route, asset, amount, and recipient, then submit the required on-chain transactions. For an ERC-20 deposit, you sign two transactions: an approval that gives the bridge contract an allowance, followed by the deposit; the ERC-20 token standard defines the approval and transferFrom functions used for this pattern.

On deposit, the L1 bridge escrows the asset and emits a cross-domain message; Metis sequencers process it, credit the destination address, and batch network data back to Ethereum. A withdrawal reverses the flow: the Metis-side asset is debited, the L2 state is committed and must pass its challenge window, then the Ethereum-side asset is released, sometimes through a separate claim or relay transaction. Keep the first transaction hash as the receipt for the later steps.

To deposit, switch your wallet to Ethereum mainnet, hold enough ETH for the approval plus the deposit gas, and submit both transactions. After L1 confirmation and sequencer processing, the funds appear at the same address on Andromeda, typically within minutes; METIS is not required beforehand because the credit happens automatically.

METIS is required for activity after the deposit because every Andromeda transaction — including swaps, transfers, and the withdrawal — pays gas in METIS. Bridge a small amount of METIS first or alongside the main asset so the received funds can be moved immediately.

A canonical withdrawal from Andromeda to Ethereum takes about seven days because the optimistic-rollup state commitment remains open to fraud proofs during its challenge window; this is finalization time, not a transaction queue. The funds remain pending until the L2 state is treated as final.

Third-party liquidity bridges can return funds to Ethereum faster by fronting L1 liquidity for a fee, while the canonical route keeps the challenge-window model. For a canonical withdrawal, track the status in the interface and complete any final claim or relay transaction after the window closes. The optimistic rollup documentation explains why the challenge period exists.

Depositing costs Ethereum mainnet Ethereum gas fees for the approval on ERC-20 assets and for the deposit transaction, with the total varying with L1 congestion. ETH deposits skip the approval step. On Andromeda, gas is paid in METIS and is inexpensive relative to mainnet.

A canonical withdrawal costs L2 gas to initiate and may also require L1 gas for a final claim or relay transaction after the challenge window. Third-party bridges add a provider fee to gas in exchange for fast liquidity. The canonical route has no bridge protocol commission beyond the gas described above.

Metis Bridge has published audits and inspectable on-chain contracts, but its trust model still includes smart-contract, upgrade, validation, and operational risk. The design inherits Ethereum data availability and uses fraud proofs to secure the L2 state; permissioned Metis actors hold upgrade and validation powers. L2BEAT's Metis analysis details those assumptions.

The practical checks are specific: use the official interface, verify that the contract address you approve matches the documented L1 Standard Bridge proxy 0x3980c9ed79d2c191A89E02Fa3529C60eD6e9c04b, and start with a small test amount. Your keys remain in your wallet, while bridge contracts hold deposited assets in transit; for an ERC-20, an unlimited approval also gives the spender allowance beyond the intended deposit.

Wrong network selected. Deposits start from Ethereum (chain ID 1), and withdrawals start from Andromeda (chain ID 1088); switching the wallet to the route's source chain fixes a session that shows no route or fails immediately.

Funds arrived but you cannot transact. Andromeda transactions require METIS for gas, so bridge a small amount of METIS or acquire it before using the received asset.

Withdrawal pending for days. The canonical route's ~7-day challenge window is the expected wait; check the withdrawal status and complete any final claim transaction after finalization.