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Overview

If you already have a testnet wallet funded on a supported network, you can skip this guide entirely. This guide uses Arbitrum Sepolia because it is a reliable testnet corridor, but other networks are supported — see Supported networks.

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Prerequisites

  • Any EVM-compatible browser wallet (MetaMask, Coinbase Wallet, Rainbow, etc.)
  • About 15–30 minutes (most of it waiting for a bridge transfer)

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Testnet vs mainnet

Testnet tokens behave exactly like real tokens but have no monetary value. Some faucets require a small mainnet ETH balance as an anti-spam measure. Your 0x address is the same on every EVM network — you don’t need a separate address for Arbitrum Sepolia. Only the balances are separate per network.

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1. Get your wallet address and private key

  1. Open your wallet and copy your 0x address. You will use this same address as both sender and recipient in the quickstart.
  2. Export your private key from your wallet’s settings. You will need it for the .env file in the next guide.
Never share your private key or commit it to a git repo. Use a testnet-only wallet — never one holding real funds.

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2. Add Arbitrum Sepolia

Add the network from chainlist.org (search “Arbitrum Sepolia”, enable testnets, click Add to MetaMask or your wallet’s equivalent). Or add manually:

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3. Get Arbitrum Sepolia ETH

The quickest path is to get Ethereum Sepolia ETH from a faucet, then bridge it to Arbitrum Sepolia. Get Sepolia ETH:
  1. Go to sepolia-faucet.pk910.de
  2. Paste your 0x address → run the mining task → Claim
  3. Switch to Sepolia in your wallet and confirm ETH arrived
Bridge to Arbitrum Sepolia:
  1. Go to bridge.arbitrum.io
  2. Connect your wallet on Sepolia, enable Testnet mode if needed
  3. Bridge about half your ETH — keep some for bridge gas
  4. Wait 10–20 minutes, then switch to Arbitrum Sepolia to confirm

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4. Get USDC on Arbitrum Sepolia

  1. Switch to Arbitrum Sepolia in your wallet
  2. Go to faucet.circle.com → connect wallet → select Arbitrum Sepolia + USDC → request
  3. Circle sends 20 USDC (one request per address every 2 hours)
You may need to add USDC as a custom token in your wallet:
  • Address: 0x75faf114eafb1BDbe2F0316DF893fd58CE46AA4d
  • Symbol: USDC, decimals: 6
If public faucets block your wallet, ask your Atum contact to send Arbitrum Sepolia ETH and USDC directly to your 0x address.

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Success criteria

On Arbitrum Sepolia, same account:
  • ETH balance (any amount)
  • USDC balance (≥ 0.01 USDC)

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Next step

Using the CLI — install the client, configure your .env, and send your first payment.