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This bridge is specifically for testnet purposes. Use free testnet ETH to test your applications before deploying to mainnet.

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How to Bridge

1

Visit the Testnet Bridge

Go to testnet.bridge.b3.fun to access the official testnet bridge interface.
2

Connect your Wallet

Connect your wallet (MetaMask, Coinbase Wallet, etc.) to the bridge interface.
Make sure your wallet is connected to either Base Sepolia or B3 Testnet depending on which direction you want to bridge.
3

Choose Bridge Direction

Select whether you want to:
  • Deposit: Bring funds from Base Sepolia → B3 Testnet
  • Withdraw: Bridge back from B3 Testnet → Base Sepolia
Click either the Deposit or Withdraw tabs accordingly.
4

Enter Amount

Enter the amount of ETH you want to bridge.

Need Base Sepolia ETH?

If you need Base Sepolia ETH, use a Base Sepolia faucet to get free testnet tokens
5

Confirm Transaction

Click “Deposit” (or “Withdraw”) and confirm the transaction prompt that appears in your wallet.
Double-check that you’re on the correct testnet and using testnet ETH, not mainnet funds.
6

Wait for Completion

Wait a few minutes for the bridge process to complete. You can check the status in your “History” tab.
Your testnet ETH will appear in your wallet on the destination network within a few minutes.

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Network Information

Base Sepolia Testnet

Chain ID: 84532
RPC: https://sepolia.base.org
Explorer: https://sepolia.basescan.org

B3 Sepolia Testnet

Chain ID: 1993
RPC: https://testnet-rpc.b3.fun
Explorer: https://testnet-explorer.b3.fun

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Testnet Resources

Testnet Bridge

Official bridge for moving assets between Base Sepolia and B3 Testnet

B3 Testnet Faucet

Get free B3 testnet ETH for development and testing

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Additional Faucets

If you need testnet ETH for development, here are some reliable faucet options:
  • B3 Testnet Faucet - Official B3 testnet faucet
  • Get free B3 testnet ETH directly without bridging

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Troubleshooting

  • Check the transaction status on the block explorer
  • Verify you’re connected to the correct testnet
  • Try increasing gas fees if the transaction is pending
  • Contact support if the bridge has been pending for over 30 minutes
  • Ensure your wallet supports the testnet networks
  • Try refreshing the page and reconnecting
  • Check that you’re on the correct network in your wallet
  • Clear your browser cache if issues persist
  • Make sure you have enough ETH to pay for gas fees
  • Use a faucet to get more testnet ETH
  • Try bridging a smaller amount to conserve gas

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Development Workflow

1

Get Base Sepolia ETH

Use a Base Sepolia faucet to get free testnet ETH.
2

Bridge to B3 Testnet

Use the testnet bridge to move ETH from Base Sepolia to B3 Testnet.
3

Deploy and Test

Deploy your contracts and test your applications on B3 Testnet.
4

Ready for Mainnet

When testing is complete, deploy to B3 Mainnet using the mainnet bridge.
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