Optimism Wallet: Send ETH and OP on OP Mainnet Safely

How addresses work on OP Mainnet

OP Mainnet is EVM-equivalent, so accounts look and behave exactly like Ethereum accounts. Your address is a 0x address with 40 hexadecimal characters, and the mixed upper and lower case letters are a checksum that catches typos. Keylo shows the same address for OP Mainnet as for Ethereum and every other EVM network, because they all derive from the same recovery phrase on the standard path.

There is nothing to activate and no reserve to keep. What you must keep in mind is that each network has its own ledger. If a friend sends OP to your address on Ethereum, it appears under Ethereum in Keylo, not under OP Mainnet. Exchanges may label the network Optimism, OP Mainnet or OP; those all mean the same chain, chain ID 10.

Create an OP Mainnet wallet with Keylo

1. 1

   Open Keylo registration in a browser on any device; there is no extension or app to install.

2. 2

   Sign up with your name, email, phone and a password, then click the confirmation link in your email.

3. 3

   Your wallet and 12-word recovery phrase are created inside your browser and encrypted with a key derived from your password before anything is saved.

4. 4

   Back up the phrase from Settings after re-entering your password. Keep it offline. It is the only way to restore the wallet if you ever forget the password.

5. 5

   Select OP Mainnet in the network list to see your 0x address and balances.

How to receive ETH or OP on Optimism

If you already hold ETH on Ethereum and want it on OP Mainnet instead, you do not need a new address. Bridge it to the same 0x address and it will appear under OP Mainnet. The Ethereum wallet guide explains how mainnet fees compare, which helps when deciding whether a small deposit is worth bridging at all.

1. 1

   In Keylo, open OP Mainnet and tap the asset you want to receive, for example ETH, OP or USDC.

2. 2

   Tap Receive to see your address and QR code. The network name OP Mainnet is shown next to it.

3. 3

   Share the address or QR code with the sender.

4. 4

   If you are withdrawing from an exchange, select Optimism or OP Mainnet as the network. Selecting ERC20 or Ethereum sends the funds to mainnet instead.

5. 5

   Watch Activity for the incoming transaction, then open it in the block explorer if you want to see the details.

How to send ETH on OP Mainnet

1. 1

   Choose OP Mainnet in Keylo and pick ETH or a token.

2. 2

   Paste the destination address or scan its QR code. Keylo validates the checksum and flags contract addresses so you do not send to a token contract by mistake.

3. 3

   Type an amount or use Max, which leaves room for the fee.

4. 4

   Choose slow, normal or fast. Two-second blocks mean even slow transactions usually confirm quickly.

5. 5

   Check the summary, including the network fee in ETH and the exact amount the recipient gets, then confirm.

Why OP Mainnet fees include an L1 data fee

An OP Mainnet fee has two main parts, both paid in ETH. The execution fee is gas used multiplied by the L2 base fee plus an optional priority tip, following EIP-1559. The L1 data fee covers posting your compressed transaction to Ethereum. Block explorers show it as a separate line called L1 fee, which surprises people who only look at gas price.

Since the Ecotone upgrade in 2024, data is posted in Ethereum blobs and the L1 fee is computed from both the blob fee and the regular Ethereum base fee. When Ethereum is busy, your OP Mainnet fee can rise even if OP Mainnet itself is quiet. Simple ETH transfers stay cheap because they compress well, while large contract calls with lots of data cost more. Keylo's summary shows the total before you sign.

Recent upgrades added an operator fee component that chain operators can switch on, and they tuned how the base fee reacts to heavy data use. On OP Mainnet these extras are small in practice, but they explain why two transfers a minute apart can cost slightly different amounts. If a transaction sits pending longer than you expect, picking the fast speed raises the priority tip, which is the part of the fee that buys earlier inclusion.

Tokens on OP Mainnet: OP, USDC and USDT0

OP is native to OP Mainnet; the version on Ethereum is a bridged copy, so if you want to vote or delegate in Optimism governance, the OP Mainnet token is the one that counts. Stablecoins come in versions: USDC issued natively by Circle, the older bridged USDC.e, and USDT0, the omnichain Tether token now live on OP Mainnet. You will also find WLD here, because World App ran on OP Mainnet before World Chain launched.

All of these are ERC-20 tokens that Keylo can display and send. Spam tokens with names like OP Rewards are common. They often point to sites that ask you to approve a contract or sign a message that drains your wallet. If you did not expect a token, do not interact with it.

Bridge or swap on OP Mainnet, and how withdrawals work

Keylo offers swap and bridge on OP Mainnet with quotes from LI.FI and THORChain. You see the route, expected output, minimum received and every fee, including any small Keylo service fee, before you confirm, and you can track a bridge until it arrives. Failed cross-chain routes are refunded by the protocol to the sending wallet.

The official Standard Bridge works differently. Deposits from Ethereum arrive in a few minutes. Withdrawals take three steps: you start on OP Mainnet, wait about an hour for the state to be proposed, send a prove transaction on Ethereum, wait out the seven-day challenge period, then send a finalize transaction on Ethereum. Both Ethereum steps cost mainnet gas. Liquidity bridges skip that wait because a relayer pays you on the destination chain.

Moving between OP Mainnet and another OP Stack chain, such as Unichain or Ink, still counts as a bridge even though the networks share code and your address. Each chain keeps its own balance, and the official route between two layer 2 networks goes through Ethereum, with the seven-day wait on the way out. For hops between rollups, a liquidity route from the quote screen is usually the practical choice.

Practice with OP Sepolia

Keylo's testnet mode adds OP Sepolia to your network list. Test ETH has no value, so you can try sending, receiving and reading fee summaries risk-free. It is also a good way to watch the L1 data fee behave on a quiet test network before you move real funds on mainnet.

Safety tips for Optimism users

• Pick Optimism or OP Mainnet at the exchange, and confirm the token is supported on that network.
• Delegate OP voting power on OP Mainnet only through the official governance site you typed yourself.
• Watch for fake OP airdrop tokens and never approve contracts linked from token names.
• Plan ahead for withdrawals through the official bridge: you need ETH on Ethereum for the prove and finalize steps.
• Keep your recovery phrase offline. Keylo staff never ask for it; use Keylo support if you need help.

Frequently asked questions