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Arc Router

Trustless cross-chain USDC transfers in seconds, powered by Arc L1 and Circle CCTP V2.

Built for ETHGlobal HackMoney 2026 — Arc Prize Track

What is Arc Router?

Arc Router treats multiple blockchains as a single liquidity surface. Users deposit USDC on any supported chain, and it arrives on the destination chain — all routed through Arc L1 as a settlement hub.

No bridges. No wrapped tokens. Native USDC on every chain, powered by Circle's CCTP V2.

How it works

Source Chain          Arc L1              Destination Chain
(Ethereum/Base/      (Settlement          (Ethereum/Base/
 Arbitrum)            Hub)                 Arbitrum)

  User burns   ──►  USDC settles  ──►   USDC minted
  USDC via           on Arc via          on destination
  CCTP V2            receiveMessage      via CCTP V2

     Hop 1              ArcRouter            Hop 2
  (depositForBurn)    (routeTransfer)     (receiveMessage)
  1. Hop 1 — User calls depositForBurn on the source chain. CCTP V2 burns USDC and emits a message.
  2. Settlement — The relayer picks up Circle's attestation via the Iris API and calls receiveMessage on Arc, minting USDC there.
  3. Hop 2 — The ArcRouter contract on Arc approves and burns USDC via depositForBurn toward the destination chain.
  4. Delivery — The relayer gets the second attestation and calls receiveMessage on the destination chain. USDC is minted to the recipient.

Total time: ~60-90 seconds on testnet (limited by Circle attestation speed).

Demo

https://github.com/user-attachments/assets/demo-placeholder

Connect wallet → Pick source/destination chains → Enter amount and recipient → Send → Watch the animated transfer progress in real-time.

Architecture

┌─────────────────────────────────────────────────────────┐
│                     Frontend (Next.js)                   │
│  ┌──────────┐  ┌──────────┐  ┌────────────────────────┐ │
│  │ Transfer  │  │ Transfer │  │  Wallet (RainbowKit +  │ │
│  │   Form    │  │ Animation│  │  Wagmi + MetaMask)     │ │
│  └────┬─────┘  └────▲─────┘  └────────────────────────┘ │
│       │              │                                    │
│  ┌────▼─────┐  ┌────┴─────┐                             │
│  │useTransfer│  │useTransfer│                            │
│  │  (hooks) │  │  Status   │                             │
│  └────┬─────┘  └────▲─────┘                             │
│       │              │                                    │
│  ┌────▼──────────────┴─────┐                             │
│  │     API Routes          │                             │
│  │  POST /api/transfers    │                             │
│  │  GET  /api/transfers/:id│                             │
│  └────┬──────────────▲─────┘                             │
│       │              │                                    │
│  ┌────▼──────────────┴─────┐                             │
│  │    SQLite (Prisma)      │                             │
│  └────┬──────────────▲─────┘                             │
└───────┼──────────────┼───────────────────────────────────┘
        │              │
┌───────▼──────────────┴───────────────────────────────────┐
│                     Relayer                               │
│                                                           │
│  ┌─────────┐    ┌──────────┐    ┌─────────────────────┐  │
│  │  Hop 1  │───►│ ArcRouter│───►│      Hop 2          │  │
│  │ Attest  │    │  on Arc  │    │  Attest + Relay     │  │
│  │ + Relay │    │  (burn)  │    │  to Destination     │  │
│  └─────────┘    └──────────┘    └─────────────────────┘  │
│                                                           │
│  Polls Circle Iris API ←──── CCTP V2 Attestations        │
└───────────────────────────────────────────────────────────┘

┌───────────────────────────────────────────────────────────┐
│                  Smart Contracts                          │
│                                                           │
│  ArcRouter.sol (Arc Testnet)                             │
│  ├── routeTransfer() — Approve + burn USDC via CCTP V2  │
│  ├── setRelayer()    — Update authorized relayer         │
│  └── withdrawUsdc()  — Emergency withdrawal              │
│                                                           │
│  Uses Circle's deployed contracts:                        │
│  ├── TokenMessengerV2  (depositForBurn)                  │
│  └── MessageTransmitterV2 (receiveMessage)               │
└───────────────────────────────────────────────────────────┘

Supported Networks

Chain Chain ID CCTP Domain USDC Address
Ethereum Sepolia 11155111 0 0x1c7D4B196Cb0C7B01d743Fbc6116a902379C7238
Arbitrum Sepolia 421614 3 0x75faf114eafb1BDbe2F0316DF893fd58CE46AA4d
Base Sepolia 84532 6 0x036CbD53842c5426634e7929541eC2318f3dCF7e
Arc Testnet 5042002 26 0x3600000000000000000000000000000000000000

Deployed Contracts

Contract Network Address
ArcRouter Arc Testnet 0x3E56fdBc57231570f56A1FCbe02251D32A4B273c

Circle CCTP V2 contracts (same on all testnets):

  • TokenMessengerV2: 0x8FE6B999Dc680CcFDD5Bf7EB0974218be2542DAA
  • MessageTransmitterV2: 0xE737e5cEBEEBa77EFE34D4aa090756590b1CE275

Tech Stack

Layer Technology
Frontend Next.js 14, React 18, TailwindCSS, Framer Motion, shadcn/ui
Wallet RainbowKit, Wagmi v2, Viem
Backend / API Next.js API Routes
Database SQLite via Prisma ORM
Relayer Node.js (tsx), Viem wallet/public clients
Smart Contracts Solidity 0.8.24, Foundry (forge)
Monorepo pnpm workspaces, Turborepo
Attestation API Circle Iris V2 Sandbox

Project Structure

arc-router/
├── apps/web/                    # Next.js frontend + API + relayer
│   ├── src/
│   │   ├── app/                 # Pages, layout, API routes
│   │   │   ├── page.tsx         # Main transfer page (form + animation)
│   │   │   ├── api/transfers/   # REST API for transfer tracking
│   │   │   └── providers.tsx    # Wagmi + RainbowKit + React Query
│   │   ├── components/
│   │   │   ├── transfer/        # TransferAnimation
│   │   │   ├── layout/          # Header (Arc logo + ConnectButton), Footer
│   │   │   └── ui/              # Button, Popover (shadcn/ui)
│   │   ├── hooks/               # React hooks (all the blockchain logic)
│   │   │   ├── useTransfer.ts   # Approve → burn → submit orchestration
│   │   │   ├── useUsdcBalance.ts
│   │   │   ├── useUsdcApproval.ts
│   │   │   ├── useDepositForBurn.ts
│   │   │   └── useTransferStatus.ts
│   │   ├── relayer/             # Offchain relayer process
│   │   │   ├── index.ts         # Main loop
│   │   │   ├── hop1.ts          # Source → Arc attestation + relay
│   │   │   ├── hop2.ts          # Arc → Destination burn + relay
│   │   │   ├── clients.ts       # Viem wallet/public clients
│   │   │   └── utils.ts         # Attestation polling, helpers
│   │   └── lib/                 # Shared utilities
│   │       ├── chains.ts        # Chain display info
│   │       ├── transferStatus.ts # Status → animation step mapping
│   │       ├── utils.ts         # cn() utility
│   │       └── wagmi.ts         # Wagmi config
│   └── prisma/
│       └── schema.prisma        # Transfer database model
├── packages/
│   ├── contracts/               # Foundry project
│   │   ├── src/ArcRouter.sol    # Main contract
│   │   ├── test/ArcRouter.t.sol # Forge tests
│   │   └── script/Deploy.s.sol  # Deployment script
│   └── shared/                  # Shared constants, types, ABIs
│       └── src/
│           ├── constants.ts     # Contract addresses, CCTP domains
│           ├── types/           # Transfer type definitions
│           └── abis/            # Contract ABIs
└── turbo.json                   # Turborepo config

Getting Started

Prerequisites

  • Node.js >= 18
  • pnpm >= 9
  • Foundry (for contract deployment)
  • A wallet with testnet ETH on the chains you want to test

1. Clone and install

git clone https://github.com/your-username/arc-router.git
cd arc-router
pnpm install

2. Set up environment

cp .env.example apps/web/.env

Edit apps/web/.env:

DATABASE_URL="file:./dev.db"
NEXT_PUBLIC_WALLETCONNECT_PROJECT_ID=""     # Get from cloud.walletconnect.com
RELAYER_PRIVATE_KEY="0x..."                 # Private key for the relayer EOA
NEXT_PUBLIC_ARC_ROUTER_ADDRESS="0x3E56fdBc57231570f56A1FCbe02251D32A4B273c"
CCTP_ATTESTATION_API="https://iris-api-sandbox.circle.com"
ARC_TESTNET_RPC_URL="https://rpc.testnet.arc.network"

3. Set up database

cd apps/web
pnpm db:generate
pnpm db:push

4. Deploy ArcRouter (optional — already deployed)

cd packages/contracts
export RELAYER_ADDRESS=0xYourRelayerAddress
forge script script/Deploy.s.sol:DeployScript \
  --rpc-url https://rpc.testnet.arc.network \
  --private-key $DEPLOYER_PRIVATE_KEY \
  --broadcast -vvv

5. Run the app

In one terminal — start the web app:

cd apps/web
pnpm dev

In another terminal — start the relayer:

cd apps/web
pnpm relayer

Open http://localhost:3000.

How to Use

  1. Connect your wallet using the button in the top-right corner
  2. Select source and destination chains from the dropdowns
  3. Enter the USDC amount — your balance is shown automatically
  4. Enter the recipient address (can be your own address on the destination chain)
  5. Click Send — MetaMask will prompt for two transactions:
    • Approve USDC spending
    • depositForBurn (burns USDC on source chain)
  6. Watch the animation as the transfer progresses through 4 stages:
    • Depositing → Settling on Arc → Sending → Delivered
  7. The relayer handles everything else automatically

Transfer Lifecycle

User Action          Status              What Happens
─────────────────────────────────────────────────────────────
Click "Send"    →    ATTESTING_HOP1      USDC burned on source chain
                                         Relayer polls Iris API for attestation
                →    RELAYING_TO_ARC     Attestation received, relaying to Arc
                →    SETTLED_ON_ARC      USDC minted on Arc
                →    BURNING_ON_ARC      ArcRouter burns USDC toward destination
                →    ATTESTING_HOP2      Relayer polls for second attestation
                →    RELAYING_TO_DEST    Attestation received, relaying to dest
                →    COMPLETED           USDC minted on destination chain

Smart Contract

ArcRouter.sol

Deployed on Arc Testnet. Called by the relayer after hop 1 settlement.

function routeTransfer(
    bytes32 transferId,     // Unique transfer ID for tracking
    uint256 amount,         // USDC amount (6 decimals)
    uint32 destinationDomain, // CCTP domain of destination
    bytes32 recipient       // Recipient address (bytes32-padded)
) external onlyRelayer

Flow: Checks USDC balance → Approves TokenMessengerV2 → Calls depositForBurn → Emits TransferRouted event.

Running Tests

cd packages/contracts
forge test -vvv

Prize Category

Best Chain Abstracted USDC Apps Using Arc as a Liquidity Hub ($5,000)

Arc Router uses Arc L1 as a central liquidity hub for USDC. Instead of point-to-point bridges between every chain pair, all transfers route through Arc — creating a single settlement layer that connects Ethereum, Base, and Arbitrum.

  • Users don't need to know about Arc — they pick source and destination chains, and the routing is handled automatically
  • USDC is never wrapped or synthetic — it's native Circle USDC on every chain via CCTP V2
  • The ArcRouter contract on Arc acts as the hub, receiving USDC from any chain and forwarding it to any other supported chain
  • The relayer automates the two-hop process, polling Circle's Iris API and submitting relay transactions

Team

Built by Siddharth at ETHGlobal HackMoney 2026.

License

MIT

About

Send USDC from any chain to any chain, settled instantly on Arc.

arc-router.vercel.app

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