Skip to main content
Add Arc as a supported blockchain for buy and sell orders in your on/off-ramp service. Arc shares its EVM foundations with networks you already support, but its native USDC model and deterministic finality simplify your integration and improve the end-user experience.

​
Prerequisites

Before you begin, ensure that you’ve:
  • Gained familiarity with EVM-based blockchain integrations.
  • Reviewed the EVM differences page for Arc-specific protocol behavior.
  • Obtained access to Arc RPC endpoints for deposit monitoring and transaction broadcasting.
  • Set up infrastructure for deposit detection and withdrawal processing on EVM blockchains.
  • Installed the viem TypeScript library (used in the address validation example).

​
Steps

​
Configure network parameters

Register Arc with the following parameters in your platform’s chain registry:
Arc uses USDC as both the native gas token and the primary transfer asset. There is no separate gas token like ETH. Configure your platform with a single asset entry for USDC on Arc.

​
Detect deposits for buy orders

When a user completes a fiat purchase and you need to detect the resulting onchain USDC deposit, use the same Transfer event monitoring pattern used by exchanges. Every native USDC movement emits a standard ERC-20 Transfer(address,address,uint256) event from the system emitter 0xffff…fffe. Arc implements EIP-7708, an Ethereum Improvement Proposal that unifies native value movements and ERC-20 token transfers into a single standard Transfer event. This covers native sends and the native leg of ERC-20 transfers. Key points for ramp deposit detection:
  • Subscribe to blocks using WebSocket (eth_subscribe("newHeads")) or poll using HTTP.
  • Filter Transfer events on the native USDC system emitter (0xfffffffffffffffffffffffffffffffffffffffe). Do not filter on the ERC-20 contract (0x3600…0000), which misses plain native sends.
  • Credit immediately after 1 confirmation. Arc’s deterministic finality guarantees no reorgs.
  • The value field uses 18 decimals (native). Divide by 10^12 for 6-decimal USDC.
For complete implementation details including code samples, address generation, and sweep logic, see Detect and process deposits.

​
Process withdrawals for sell orders

When a user sells crypto for fiat and you need to send USDC to a settlement address or back to the user, the withdrawal flow is identical to exchange withdrawals:
  1. Validate the destination address (EIP-55 checksum).
  2. Check the blocklist before sending.
  3. Build and sign a native USDC transfer (the recommended path, cheaper in gas and universally receivable).
  4. Broadcast and confirm (single confirmation = final).
You pay gas fees in USDC from the same balance. No need to maintain a separate ETH float for gas. For complete implementation details including transaction construction and gas estimation, see Process withdrawals.

​
Display Arc in your UI

Arc’s native USDC model affects how you present the network to end users:
Because there is no separate gas token, you can skip the “ensure you have ETH for gas” warning that other EVM blockchains require. Users receive USDC and can immediately transfer it without acquiring a second asset.

​
Configure settlement timing

Arc provides sub-second deterministic finality. Once a transaction is included in a block, it is final. There are no reorgs, no probabilistic confirmation windows, and no need to wait for additional blocks. For your ramp platform, this means:
  • Buy orders: Credit the user’s crypto balance immediately upon 1 confirmation.
  • Sell orders: Mark the withdrawal as complete after the transaction receipt is returned.
  • Settlement display: Show instant confirmation to the user rather than a progress bar or block countdown.

​
Validate addresses

Arc uses standard Ethereum addresses:
  • 20 bytes, 0x-prefixed (42 characters total).
  • EIP-55 mixed-case checksum encoding.
  • Compatible with existing Ethereum address validation logic in your platform.
No additional address format validation is required beyond what you already implement for EVM blockchains.

​
Screen for compliance

Arc enforces a USDC blocklist at multiple levels:
  • Pre-mempool: Transactions from or to blocklisted addresses are rejected before entering the mempool.
  • Runtime: Transfers involving blocklisted addresses revert during execution.
Your platform should check addresses against the onchain blocklist before initiating withdrawals. If a destination is blocklisted, the transaction reverts and gas is consumed without transferring funds. For implementation details on blocklist monitoring and event subscription, see Monitor blocklist compliance.
Always verify destination addresses against the blocklist before broadcasting withdrawal transactions. Sending to a blocklisted address wastes gas fees and creates a failed transaction that you must handle in your reconciliation flow.

​
Route USDC crosschain

If your platform supports crosschain transfers (for example, a user buys USDC on Ethereum and wants delivery on Arc), use Circle’s Cross-Chain Transfer Protocol (CCTP), a permissionless onchain utility that enables USDC to move natively between supported blockchains. Arc’s CCTP domain is 26. For bridging implementation details, see Bridge USDC with CCTP.