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Kyber Network

Interface

contract KyberNetworkProxy {
    function swapEtherToToken(address token, uint256 minConversionRate) public payable returns(uint256);
    function swapTokenToEther(address token, uint256 srcAmount, uint256 minConversionRate) public returns(uint256);
    function swapTokenToToken(address src, uint256 srcAmount, address dest, uint256 minConversionRate) public returns(uint256)
    function trade(address src, uint256 srcAmount, address dest, address destAddress, uint256 maxDestAmount, uint256 minConversionRate, address walletId) public payable returns(uint256);
    function tradeWithHint(address src, uint256 srcAmount, address dest, address destAddress, uint256 maxDestAmount, uint256 minConversionRate, address walletId, bytes hint) public payable returns(uint256);
    function maxGasPrice() public view returns(uint256);
    function getExpectedRate(address src, address dest, uint srcQty)public view returns(uint expectedRate, uint slippageRate)
}
//glossary
bytes public constant PERM_HINT = "PERM";
address ETH_TOKEN_ADDRESS = ERC20(0x00eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee);
address registerReferral = 0xECa04bB23612857650D727B8ed008f80952654ee;
contract registry{
    function registerWallet(address wallet) external;
}

KyberNetwork is an exchange aggregator provides nearly best rate from multiple onchain liquidity providers. You may do both ERC20 to Eth or ERC20 to ERC20 swap via KyberNetwork. KyberNetwork also relays swaps to permissionless exchanges like Uniswap and Oasis DEX, so exchange rate is always the same or better, but the drawback is its gas consuption is considerably higher. (50K -> 500K)



Registry

KyberNetwork has a referral program. Anyone may register as a referrer and gain fee rebate from each trade that includes their address as a referral code.

Referral would be calculated/sent in KNC, the native token of KyberNetwork.

Registry address: 0xECa04bB23612857650D727B8ed008f80952654ee

Use registerWallet(address wallet) to register.

You may register for other's address.

Register as a referrer on Kyber Network


Proxy

KyberNetwork constantly upgrades its exchange contract implementation, to mitigate integration overhead, there's a proxy contract that delegates trade to an implementation. It's better for contracts to interact with Kyber Proxy insteand of the underlying contract, so it won't get affected when migration occurs.

Kyber Proxy Contract Address : 0x818E6FECD516Ecc3849DAf6845e3EC868087B755



Ether address used by Kyber Network

Since the native asset, Eth, doesn't have an token address, Kyber uses 0x00eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee to represent Eth.

When using Eth address as src, you MUST send Eth (msg.value) along with the function call.



Functions

trade

Core function of KyberNetwork

ParamsTypeDescription
srcaddressaddress of token to spend
srcAmountuint256amount to spend
destaddressaddress of token you want to buy
destAddressaddressreceiver address
maxDestAmountuint256amount of dest bought must be lower than this
minConversionRateuint256conversion rate (destAmount / srcAmount * 1e18) must be larger than this
walletIdaddressaddress of your referrer
ReturnsTypeDescription
uint256the exact amount of token bought

tradeWithHint

In KyberNetwork, there's two kind of reserve: permissioned and permissionless. Because anyone can initiate a permissionless reserve, searching best price in it may cost a lot of gas. If you only want to trade with permissioned liquidity provider, use tradeWithHint().

hint

Input "PERM" into the bytes hint param to filter permissionless reservers.


swapEtherToToken / swapTokenToEther / swapTokenToToken

Wrapped function of trade(), fewer params, fewer gas consuption. Note that they do not filter permissionless liquidity providers.


maxGasPrice

To prevent severe front-running, KyberNetwork will block trades that have gas price exceed a certain amount. The max gas price is maintained by admin (or DAO). You may use maxGasPrice to check the current number.


getExpectedRate

Get current exchange rate of two tokens without executing any trade.

ParamsTypeDescription
srcaddressaddress of token you want to spend
destaddressaddress of token you want to buy
srcQtyuinttoken amount to spend
ReturnsTypeDescription
expectedRateuintexpected exchange rate (destQty / srcQty * 1e18)
slippadeRateuintexchange rate in worst case (destQty / srcQty * 1e18)


Use Cases

Buy Compound DAI with Eth in a single transaction

contract BuycDAI {
    Exchange Kyber = Exchange(0x818E6FECD516Ecc3849DAf6845e3EC868087B755);
    Erc20 dai = Erc20(0x6B175474E89094C44Da98b954EedeAC495271d0F);
    CErc20 cDai = CErc20(0x5d3a536E4D6DbD6114cc1Ead35777bAB948E3643);
    address etherAddr = 0x00eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee;
    address owner;
    constructor() public {
        owner = msg.sender; //must register to gain reward
        dai.approve(address(cDai), uint256(-1));
    }
    function () public payable {
        uint256 amount =
        Kyber.trade.value(msg.value)(etherAddr, msg.value, address(dai), address(this), 10**28, 1, owner);
        cDai.mint(amount);
        amount = cDai.balanceOf(address(this));
        cDai.transfer(msg.sender, amount);
    }
}

Related Tools

Register as a referrer on Kyber Network