CCTP — Any chain in, settle on Arc

Pairband uses Circle CCTP v2 so users can fund trades from Ethereum, Base, Unichain, Arbitrum, Optimism, Solana, and other supported domains without holding Arc USDC upfront.

Tokens never leave Arc. Only USDC moves cross-chain; ERC-20 launch tokens are minted and traded natively on Arc.

Flow

Source chain                Arc (domain 26)
─────────────               ─────────────────
User USDC  ──burn──►  TokenMessenger  ──mint──►  PairbandSettler
                                                      │
                                                      ├─► Launchpad (curve buy)
                                                      └─► Book / pair (post-grad)

1. User approves USDC on the source chain
2. CCTP burns source USDC and attestation is relayed
3. Arc mints native USDC to PairbandSettler
4. Settler routes into PairbandLaunchpad or post-graduation venues
5. User receives tokens or book credit on Arc

Bridge out burns Arc USDC and mints on the destination domain — tokens still do not bridge.

Arc constants

Parameter	Value
Arc CCTP domain	26
TokenMessenger (Arc)	0x8FE6B999Dc680CcFDD5Bf7EB0974218be2542DAA
USDC on Arc	0x3600000000000000000000000000000000000000
Settler contract	See Contracts — filled after deployment

Supported source domains (preview)

The app config includes common CCTP sources, for example:

Chain	Notes
Ethereum	Fast Transfer eligible
Base	Fast Transfer eligible
Unichain	Fast Transfer eligible
Arbitrum	Standard transfer
Optimism	Standard transfer
Solana	Domain-specific CCTP flow

Exact domain IDs and messenger addresses on source chains follow Circle's CCTP documentation. Always verify live addresses before mainnet use.

Fast vs standard transfer

Mode	Latency	When
Fast Transfer	Seconds	Supported pairs (e.g. ETH, Base, Unichain → Arc)
Standard	Minutes	Chains without fast path

The preview app may settle CCTP instantly for demo purposes. Production follows Circle attestation timing.

Security notes

• Only PairbandSettler should receive minted USDC from CCTP for protocol routing — verify bytecode and ownership after deploy
• Never paste private keys in apps, docs, or env files committed to git
• Test every new domain on Arc Testnet (5042002) before mainnet

Related

• Quickstart — faucet and first trade
• Architecture — settler role in the stack
• Contracts — per-chain address table