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What the bridge is

The Lunya bridge moves USDC between Arc and other EVM chains using Circle’s Cross-Chain Transfer Protocol (CCTP) v2 — the transfer mechanism operated by the issuer of USDC itself.

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How it works

1

Burn on the source chain

Your USDC is burned — destroyed, not deposited into a bridge contract — on the chain you are leaving.
2

Circle attests

Circle’s attestation service observes the burn and signs an attestation for it.
3

Mint on the destination

The attestation is presented on the destination chain, and Circle’s contract mints the same amount of USDC there.
Why this design matters:
  • No wrapped tokens — what arrives is canonical USDC, minted by Circle, not an IOU issued by a bridge
  • No third-party validator set — the only signature trusted is Circle’s, the same entity already trusted by holding USDC at all
  • No liquidity pools to drain — burn-and-mint means there is no honeypot of locked tokens on either side

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Fees and speed

  • Fees come out of the mint, not on top — the sender is debited exactly the amount they send; Circle’s fee (basis points of the amount, plus a flat forwarding charge where used) is deducted from what the recipient receives on the destination
  • Fast transfer — on chains that support it, transfers clear against a lower finality threshold instead of waiting for full source-chain finality; elsewhere, plan for the source chain’s finality time
  • The app quotes the exact fee and expected time before you send

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Supported chains

The bridge currently runs against Arc testnet — Circle’s CCTP supports Arc testnet only for now, so sources are the corresponding testnets: 21 source chains including Ethereum (Sepolia), Base, Arbitrum, Optimism, Avalanche, Polygon, Unichain, Linea, Monad, Sei, Hyperliquid, Sonic, Worldchain, Ink, and Plume. When Arc mainnet ships, the mechanism is unchanged — only the source table grows up with it.

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The decimals detail

On every source chain USDC is a 6-decimal ERC-20. On Arc it is also the native gas token, which as an EVM native has 18 decimals — the same balance simply has two views, and every figure the bridge shows is in the familiar 6-decimal USDC unit. The value never changes crossing over; only its representation does.

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Things to know

  • What arrives is canonical USDC — minted by Circle against its own attestation, not a wrapped token
  • Keep gas on the source side — the burn transaction needs the source chain’s gas token; on Arc, the USDC you receive is the gas token
  • Transfers are not instant — even fast transfers wait for a finality threshold; the app shows the expected time up front