Arc is still in its testnet phase, and all operations revolve around the testnet environment. If you see any claims about depositing mainnet assets, stop and verify with official sources first—currently, only the testnet is safe to use.
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First, understand Arc's core difference: USDC is both gas and transfer asset
On most EVM chains, you need at least two types of assets: one for gas (ETH, BNB, MATIC) and another for transfers or dApp interactions (USDC, USDT). Arc combines both—USDC is the native token of this chain. Gas is paid in USDC, and your USDC balance serves as both your balance and your gas reserve.
This means you don't need to hold ETH on Arc. When moving assets to Arc, you only need USDC.
But there's one easy-to-miss detail: USDC has two "interfaces" on Arc with different decimal places. Native gas accounting uses 18 decimals, while the standard ERC-20 interface uses 6 decimals. They point to the same balance, not two different tokens. If you see two USDC balances in your wallet, that's just the display logic listing the same asset twice—don't try to "merge" them.
For regular users, everyday transfers, receiving, and dApp operations go through the 6-decimal ERC-20 interface, which feels the same as using USDC on other chains. The 18-decimal issue only comes up when you manually set gas parameters or use developer tools.
Connecting to Arc Testnet: What to Enter in Your Wallet
When adding a custom network in MetaMask or a similar EVM wallet, enter the following information (based on the current official testnet configuration):
| Field | Value |
|---|---|
| RPC URL | https://rpc.testnet.arc.network |
| Chain ID | 5042002 |
| Currency Symbol | USDC |
| Block Explorer | https://testnet.arcscan.app |
(Source: Arc Official Docs · Connect to Arc, verified on 2026-09-19)
Some sources list the RPC as rpc.testnet.arc.io. These may correspond to different environments or historical versions. If you can't fetch data after connecting, switch to the RPC under the arc.network domain as noted in the docs.
Getting Testnet USDC
Arc testnet USDC is claimed from Circle's faucet: https://faucet.circle.com. Select Arc Testnet and enter your wallet address.
Testnet USDC has no real value and is for testing only. If someone charges you or asks you to deposit real assets in the name of "Arc mainnet USDC," it's a scam.
Crossing from Other Chains to Arc: Use CCTP, Not Third-Party Bridges
To move USDC from other chains (like Ethereum Sepolia, Base Sepolia) to Arc, the correct path is Circle's official Cross-Chain Transfer Protocol (CCTP). Arc's domain ID in CCTP is 26.
CCTP works on a "burn-and-mint" model: USDC is burned on the source chain, Circle's attestation service confirms it, and an equal amount of USDC is minted on the destination chain (Arc). No wrapped tokens are created—you receive native USDC.
If you use Circle's App Kit or Forwarding Service, the process can be simplified. The Forwarding Service handles the minting step on the destination chain for you. You only need to initiate the operation on the source chain. With useForwarder: true enabled, you can specify a receiving address to complete the cross-chain transfer even if you don't have a wallet on Arc to control the minting transaction.
If you manually go through the CCTP contract flow, you'll roughly need to: approve USDC on the source chain's TokenMessengerV2 contract and call depositForBurn, specifying domain 26 as the target. Then extract the message hash from the transaction logs, poll Circle's attestation service, and finally call the receive function on Arc to complete minting. The manual flow has many steps and is suited for developers or scenarios requiring precise control over each step.
Don't use unverified third-party bridges. For testnet assets, the risk is relatively manageable, but build the habit: before crossing chains, confirm that the target bridge explicitly supports Arc and that Arc's CCTP domain ID is 26.
Transaction Verification: Check the Block Explorer, but Understand Arc's "Instant Finality"
Arc's block explorer is https://testnet.arcscan.app. Enter a transaction hash to see details like transaction info, block confirmation, and gas consumption (denominated in USDC).
But Arc has a design that needs separate understanding: deterministic instant finality. On Ethereum, a transaction typically needs to wait for over a dozen block confirmations before being considered "safely final." On Arc, once a transaction is included in a committed block, it is in its final state—irreversible, with no need for additional confirmations. Block time is under one second, and a transaction can be considered complete once confirmed.
This has two practical implications:
First, you don't need to check "confirmation count" on the block explorer. If the transaction already appears in a block with a successful status, it's final. Seeing "0 confirmations" doesn't mean there's risk—Arc doesn't have that concept.
Second, failed transactions also consume gas. Arc handles USDC blacklisting in a special way: if a sender is blacklisted after a transaction is accepted but before execution, the transaction will revert at runtime, but gas has already been consumed. If you try to send to a flagged address, the transfer itself will revert, and the fee won't be refunded. This means "transaction failure" and "no loss" are not the same thing on Arc. Checking addresses before initiating a transaction matters more here than on other chains.
If you verify Arc transactions through data platforms like Bitquery or Dune, note that Arc's gas fees are denominated in USDC—just interpret them as USDC when querying.
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Common Sticking Points
Can't see USDC balance in wallet. Check whether you've switched to the Arc network. If you're still on Ethereum mainnet or another chain, the balance you see belongs to that chain. Arc's USDC only displays on the Arc network.
Gas fee display looks abnormal. Arc testnet has a minimum gas price floor: 20 Gwei. If developer tools or manual settings set a gas price below this value, transactions may stay stuck in pending status. Regular wallet users usually don't need to set this manually, but if you encounter errors like "transaction underpriced" when sending transactions via scripts, check whether maxFeePerGas is below 20 Gwei.
USDC hasn't arrived after cross-chain. CCTP cross-chain requires waiting for Circle's attestation service. If using the Forwarding Service, arrival time depends on the service's processing speed; manual flow requires you to actively poll attestation and submit the minting transaction. First confirm on the source chain explorer that the burn transaction succeeded, then check on the Arc explorer whether a corresponding minting transaction exists. If the source chain succeeded but the destination chain shows no response for a long time, check whether the attestation service returned proof.
Want to send to an address but it keeps failing. Besides insufficient balance, a common cause is that the address is blacklisted by the USDC contract. Arc checks whether the sender is blocked before the transaction enters the mempool—if blocked, the transaction is rejected outright and no fee is charged. If the destination address is blocked, the transaction may enter execution but the transfer reverts, and gas is consumed. Verify address status before proceeding.
