Bridge USDC to Arc Testnet Using Circle CCTP Protocol

All FlareHQ payment features — hosted checkout, streaming payments, escrow — operate on Arc testnet (chain ID 5042002). If your USDC is sitting on Ethereum, Arbitrum, or Solana, you need to bridge it across before you can use it. FlareHQ’s CCTP bridge uses Circle’s Cross-Chain Transfer Protocol to move native USDC — not a wrapped token — with 1:1 capital efficiency and no slippage.

Why Native USDC Matters

Circle’s CCTP burns USDC on the source chain and mints an equivalent amount on the destination chain. Unlike liquidity-pool bridges, there is no wrapped token, no price deviation, and no bridge liquidity ceiling. Every 1 USDC you send in is exactly 1 USDC on Arc when it arrives.

Supported Chains

Ethereum

Mainnet and Sepolia testnet supported as source chains.

Arbitrum

Arbitrum One and Arbitrum Sepolia supported as source chains.

Solana

Solana mainnet and devnet supported as source chains.

The destination chain is always ARC-TESTNET (chain ID 5042002).

Initiating a Bridge Transfer

Request Parameters

string

required

Source chain identifier. Accepted values: "ETH-MAINNET", "ETH-SEPOLIA", "ARB-MAINNET", "ARB-SEPOLIA", "SOL-MAINNET", "SOL-DEVNET".

string

required

Destination chain. Must be "ARC-TESTNET".

string

required

USDC amount to bridge, as a decimal string, e.g. "100.00".

string

required

The 0x destination wallet address on Arc testnet that will receive the bridged USDC.

Response Fields

boolean

true when the bridge transfer was initiated successfully.

string

Always "pending" on the initial response. Poll the status endpoint to track progress.

string

Unique transfer identifier. Use this with GET /api/cctp/transfer/status?id=... to check progress.

string

Human-readable instruction pointing to the status endpoint.

Example Response

{
  "success": true,
  "status": "pending",
  "id": "cctp_ref_8x2nq7w4",
  "message": "Bridge started — poll /api/cctp/transfer/status?id=cctp_ref_8x2nq7w4 to check progress."
}

Checking Transfer Status

curl "https://flarehq.xyz/api/cctp/transfer/status?id=cctp_ref_8x2nq7w4" \
  -H "Authorization: Bearer fhq_sec_..."

Status	Meaning
`pending`	Transfer initiated; source-chain burn transaction submitted
`attesting`	Circle’s attestation service is signing the burn proof
`minting`	Mint transaction submitted on Arc testnet
`completed`	USDC has arrived in the recipient’s Arc wallet
`failed`	Transfer failed; check the `error` field for details

Settlement Time

EVM source chains (Ethereum, Arbitrum) typically settle in ~2 minutes. This covers:

Source-chain finality for the burn transaction (~1 minute on Arbitrum, up to ~15 blocks on Ethereum)
Circle attestation service signing the proof (~30 seconds)
Arc testnet mint transaction confirmation (~15 seconds)

Solana transfers may take slightly longer due to attestation differences.

Getting Test USDC

You do not need mainnet USDC to test with FlareHQ. Circle provides a testnet faucet:

Go to faucet.circle.com.
Select ARC-TESTNET from the chain dropdown.
Paste your Arc wallet address and click Request Funds.
Test USDC arrives within ~30 seconds — no bridging required.

If you specifically want to test the full bridge flow, select ETH-SEPOLIA or ARB-SEPOLIA in the faucet, request test USDC there, then bridge it into Arc using the endpoint above.

Listing Supported Chains

To programmatically fetch the current list of supported source and destination chains:

curl https://flarehq.xyz/api/cctp/transfer \
  -H "Authorization: Bearer fhq_sec_..."

{
  "success": true,
  "sourceChains": [
    { "id": "ETH-SEPOLIA", "name": "Ethereum Sepolia" },
    { "id": "ARB-SEPOLIA", "name": "Arbitrum Sepolia" },
    { "id": "SOL-DEVNET",  "name": "Solana Devnet" }
  ],
  "destinationChains": [
    { "id": "ARC-TESTNET", "name": "Arc Testnet", "chainId": 5042002 }
  ]
}

Bridging is one-directional in this guide. This tutorial covers inbound transfers to Arc testnet only. To move USDC back out of Arc to another chain, initiate a separate CCTP transfer with Arc as the source and your preferred chain as the destination. Funds bridged into Arc cannot be recovered by reversing the same transfer — you must start a new outbound transfer.

Get Started

Payments

x402 Protocol

Agentic Finance

Developer Guide

Bridge USDC to Arc Testnet Using Circle CCTP Protocol

Why Native USDC Matters

Supported Chains

Ethereum

Arbitrum

Solana

Initiating a Bridge Transfer

Request Parameters

Response Fields

Example Response

Checking Transfer Status

Settlement Time

Getting Test USDC

Listing Supported Chains

​Why Native USDC Matters

​Supported Chains

Ethereum

Arbitrum

Solana

​Initiating a Bridge Transfer

​Request Parameters

​Response Fields

​Example Response

​Checking Transfer Status

​Settlement Time

​Getting Test USDC

​Listing Supported Chains

Why Native USDC Matters

Supported Chains

Initiating a Bridge Transfer

Request Parameters

Response Fields

Example Response

Checking Transfer Status

Settlement Time

Getting Test USDC

Listing Supported Chains