3. How to use an Orbit Bridge

** The chain parameter should have the following format:

ETH, ORBIT, KLAYTN, BSC, MATIC, HECO, CELO, AVAX, FANTOM, HARMONY, MOONRIVER, OEC, XDAI

EVM

Vault Contract Interface

interface IVault {
    function deposit(string memory toChain, bytes memory toAddr) payable public;
    function depositToken(address token, string memory toChain, bytes memory toAddr, uint amount) public; 
}

• You can use the vault to bridge assets to other chains which deployed minter. (ex) Bsc vault has only Klaytn, Orbit, Heco and Matic minter. (See BSC vault contracts) BNB can bridge to Heco. But cannot bridge to Fantom.

• If you want to bridge native assets like ETH or BNB, use deposit.

• Otherwise, if you want to bridge ERC20, use depositToken.

• Orbit Bridge has ETH, KLAYTN, BSC, MATIC, HECO, CELO vaults.

Details

deposit(string memory toChain, bytes memory toAddr) payable

• toChain: Chain symbol to send assets.

• toAddr: Address to receive bridged assets. ** You must send a transaction with value for the amount to be sent.

depositToken(address token, string memory toChain, bytes memory toAddr, uint amount)

• toChain: Chain symbol to send assets

• toAddr: Address to receive bridged assets

• amount: The amounts of tokens to send (wei)

Example

1. Bridge 0.1 ETH from ETH to KLAYTN

• ETH is a native asset of the Ethereum chain.

• In this case, call the deposit method to the ETH vault contract.

• contract address: 0x1bf68a9d1eaee7826b3593c20a0ca93293cb489a

deposit("KLAYTN", <to address>){value: 100000000000000000}

2. Bridge 10 BUSD from BNB to MATIC

• BUSD is an ERC20 token based on the BNB chain.

• In this case, call the depositToken method to Bsc vault contract.

• contract address: 0x89c527764f03BCb7dC469707B23b79C1D7Beb780

depositToken("MATIC", <to address>, 10000000000000000000)

Minter Contract Interface

interface IMinter {
    function getChainId(string chain) external view returns (bytes32);
    function chainFee(bytes32 chainId) external view returns (uint256);
    function getTokenAddress(bytes memory token) public view returns(address);
    function requestSwap(address tokenAddress, string memory toChain, bytes memory toAddr, uint amount) public payable;
}

• You can use the minter to send bridged assets to the origin chain or another chain.

• In this case, only use requestSwap

• Depending on the chain, there may be a chain fee.

• If there is a chain fee, you need to send a transaction by putting it in value.

• Minted Tokens have the prefix ‘o’ which means bridged by an Orbit Bridge. (oUSDT, oBUSD, oXRP, oETH etc…)

Details

getChainId(string chain)  

Returns unique bytes32 data for each chain.

• chain: Chain symbol to send assets.

chainFee(bytes32 chainId)

Returns chain fee for each chain.

• chainId: bytes32 data from getChainId method.

getTokenAddress(bytes memory token)

• token: Address of origin asset. For native assets, it is 0x0000000000000000000000000000000000000000

requestSwap(address tokenAddress, string memory toChain, bytes memory toAddr, uint amount)

• tokenAddress: Returned value using getTokenAddress

• toChain: Chain symbol to send assets.

• toAddr: Address to receive bridged assets.

• amount: The amounts of tokens to send (wei)

Example

1. Bridge 0.1 oETH from KLAYTN to ETH

• oETH on Klaytn is a bridged ERC20 token from Eth.

• ETH is a native asset of the Ethereum chain.

• In this case, use the Klaytn minter contract of Eth vault

• contract address: 0x60070F5D2e1C1001400A04F152E7ABD43410F7B9

requestSwap(
    "0x0000000000000000000000000000000000000000"
    , "KLAYTN"
    , <to address>
    , 100000000000000000 // 0.1 * 10 ** 18
){value: 100000000000000000} // chainFee

2. Bridge 10 oBUSD from MATIC to HECO

• oBUSD on Matic is a bridged ERC20 from BNB chain.

• BUSD is an ERC20 based on the BNB chain.

• To bridge oBUSD from Matic to Heco, use Matic minter contract of Bsc vault

• contract address: 0x89c527764f03BCb7dC469707B23b79C1D7Beb780

requestSwap(
    "0xe9e7CEA3DedcA5984780Bafc599bD69ADd087D56" // origin BUSD address
    , "HECO"
    , <to address>
    , 10000000000000000000 // 10 * 10 ** 18
){value: 100000000000000000} // chainFee

STACKS

Minter Contract Interface

(request-swap (to-chain (buff 256)) (to-addr (buff 20)) (amount uint))

In the case of Stacks, there is a minter corresponding to each bridged token.

• to-chain: Chain to send assets. This value can get using bufferCVFromString (see @stacks/transactions)
• to-addr: Address to receive bridged assets.