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Lease a bridge

Leasing a bridge allows you to utilize the Chromia bridge component without manually deploying it. This process replaces the step Deploy the Chromia bridge component found in the bridge deployment guide.

You still need an EVM bridge contract to interact with the leased bridge. For more information, refer to Deploy the EVM bridge component.

How leasing works​

To verify a bridge withdrawal transaction on the Chromia network from the EVM side, your EVM account must invoke the withdraw function on the bridge smart contract. You need to submit the block header of the block containing the withdrawal, along with its block signatures for verification.

The bridge forwards your function call to the Validator Contract, which interacts with the Chromia nodes. Once the Validator Contract verifies the signatures' validity, it returns the operation's result to your EVM account. This process enables you to verify specific actions on the Chromia network.

The Validator Contract maintains a list of nodes and signers on the Chromia network. To avoid issues related to updates in the network, you need to update this list either manually as a developer or automatically by creating a bridge lease.

The leasing process​

Creating a bridge lease facilitates automatic updates to the node list in the Validator Contract. Each update incurs a transaction fee, paid in CHR tokens, based on the current ETH exchange rate.

To initiate the process, visit Chromia Staking on mainnet or testnet, and connect your wallet.

Then, click Containers lease in the header. In the container list, select your required container, click the overflow menu, and choose Bridge lease.

bridge lease 1

Confirm your container selection by clicking Lease a bridge.

bridge lease 2

Specify all bridge details​

When you lease a bridge, provide the following details:

  • EVM chain
  • Chromia destination chain
  • EVM bridge contract address (see Deploy the token bridge contract)
  • Validator contract address based on your target network:
    • BSC Testnet: 0x83dB85F7ef4447524D3A31c0F4664a89173C68Eb
    • BSC Mainnet: 0xc755927508b7Ac3f7B31c9Ed396F3bE91C723d00
    • Ethereum Mainnet: 0xc755927508b7Ac3f7B31c9Ed396F3bE91C723d00

After entering all the details, click Lease bridge to finalize the process.

bridge lease 3

Final Step: Register the leased bridge on EVM​

Once you lease the bridge, you must register it on the EVM bridge contract. Follow the instructions in Register the Chromia bridge component on EVM to complete the setup.