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Trading: Exchanging Synths

To exchange any synth into sUSD in Mintr, a user does:

Alternatively, to exchange one synth for another in Synthetix.Exchange, a user does:

Via the contracts, the process is as follows:

Exchanging API

Contract

Use the Proxies

Note: The transaction's to parameter can be to either the proxy or the underlying, however two things are worth noting:

  1. the underlying is subject to change (and does most releases); and
  2. the events will always be emitted on the proxy, regardless of the to parameter in the transaction.

For best results, always interact with the proxy using the ABI of the underlying.

Destination contract (address): ProxyERC20 (preferred) or ProxySynthetix (deprecated, see this notice)

Target contract (ABI): Synthetix

Methods

Events Emitted

On a successful transaction, the following events occur:

If any fees are owing or owed, these events will come first. See trade settlement for information.

Following any reclaims or rebates, the following events then occur:

name emitted on address from address to uint value
Transfer Proxy<src> msg.sender (or user) 0x0 fromAmount
name emitted on address account uint value
Burned Proxy<src> msg.sender (or user) fromAmount
name emitted on address from address to uint value
Transfer Proxy<dest> 0x0 msg.sender (or user) toAmount - fee
name emitted on address account uint value
Issued Proxy<dest> msg.sender (or user) toAmount - fee
name emitted on address from address to uint value
Transfer ProxysUSD 0x0 FEE_ADDRESS fee
name emitted on address account uint value
Issued ProxysUSD FEE_ADDRESS fee
name emitted on address account bytes32 src uint fromAmount bytes32 dest uint toAmount address toAddress
SynthExchange ProxySynthetix msg.sender
(or user)
src fromAmount dest toAmount - fee msg.sender
(or user)

Examples from Mainnet

  • ProxySynthetix.exchange(sETH, 100e18, iETH)
  • ProxySynthetix.exchange(iETH, 0.22e18, sUSD) (with a Reclaim)
  • ProxySynthetix.exchange(sETH, 5e18, sUSD) (with a Rebate)

Code Snippets

Exchanging (Trading)

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const { SynthetixJs } = require('synthetix-js');
const privateKey = '0x' + '1'.repeat(64); // don't actually put a private key in code obviously

// parameters: default provider, default networkId, private key as a string
const networkId = 3; // ropsten, (use 1 for mainnet)
const signer = new SynthetixJs.signers.PrivateKey(null, networkId, privateKey);
const snxjs = new SynthetixJs({ signer, networkId });

const { toUtf8Bytes32, parseEther } = snxjs.utils;

(async () => {
  try {
    // send transaction
    const txn = await snxjs.Synthetix.exchange(toUtf8Bytes32('sUSD'), parseEther('0.001'), toUtf8Bytes32('iETH'));

    console.log('hash is mining', txn.hash);

    // wait for mining
    await txn.wait();

    // fetch logs of transaction
    const { logs } = await signer.provider.getTransactionReceipt(txn.hash);

    // show them
    console.log(JSON.stringify(logs, null, '\t'));
  } catch (err) {
    console.log('Error', err);
  }
})();
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const synthetix = require('synthetix'); // nodejs
const ethers = require('ethers'); // nodejs
// or using ES modules:
// import synthetix from 'synthetix';
// import ethers from 'ethers';

const network = 'ropsten';
const provider = ethers.getDefaultProvider(network === 'mainnet' ? 'homestead' : network);

const { address } = synthetix.getTarget({ network, contract: 'ProxyERC20' });
const { abi } = synthetix.getSource({ network, contract: 'Synthetix' });

const privateKey = '0x' + '1'.repeat(64); // don't actually put a private key in code obviously
const signer = new ethers.Wallet(privateKey).connect(provider);

// see https://docs.ethers.io/ethers.js/html/api-contract.html#connecting-to-existing-contracts
const Synthetix = new ethers.Contract(address, abi, signer);
const { toBytes32 } = synthetix;

(async () => {
  try {
    // send transaction
    const txn = await Synthetix.exchange(toBytes32('sUSD'), ethers.utils.parseEther('0.001'), toBytes32('iETH'));

    // wait for mining
    await txn.wait();
    // fetch logs of transaction
    const { logs } = await provider.getTransactionReceipt(txn.hash);
    // display
    console.log(JSON.stringify(logs, null, '\t'));
  } catch (err) {
    console.log('Error', err);
  }
})();
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pragma solidity 0.5.16;

import "synthetix/contracts/interfaces/IAddressResolver.sol";
import "synthetix/contracts/interfaces/ISynthetix.sol";


contract MyContract {

    // This should be instantiated with our ReadProxyAddressResolver
    // it's a ReadProxy that won't change, so safe to code it here without a setter
    // see https://docs.synthetix.io/addresses for addresses in mainnet and testnets
    IAddressResolver public synthetixResolver;

    constructor(IAddressResolver _snxResolver) public {
        synthetixResolver = _snxResolver;
    }

    function synthetixExchange(bytes32 src, uint amount, bytes32 dest) external {)
      ISynthetix synthetix = synthetixResolver.getAddress("Synthetix");
      require(synthetix != address(0), "Synthetix is missing from Synthetix resolver");

      // This check is what synthetix.exchange() will perform, added here for explicitness
      require(!synthetix.isWaitingPeriod(src), "Cannot exchange during the waiting period");

      // Exchange for msg.sender = address(MyContract)
      synthetix.exchange(src, amount, dest);

      // Note: due to Fee Reclamation in SIP-37, the following actions will fail if attempted in the
      // same block (the waiting period for the "to" synth must first expire)
        // synthetixResolver.getSynth(dest).transfer(address(0), 1e12)
        // synthetix.exchange(dest, 1e12, "sBTC");
        // synthetix.settle(dest);
    }

    function synthetixExchangeOnBehalf(address user, bytes32 src, uint amount, bytes32 dest) external {
        ISynthetix synthetix = synthetixResolver.getAddress("Synthetix");
        require(synthetix != address(0), "Synthetix is missing from Synthetix resolver");

        // This check is what synthetix.exchange() will perform, added here for explicitness
        require(!synthetix.isWaitingPeriod(src), "Cannot exchange during the waiting period");

        // Note: this will fail if `DelegateApprovals.approveExchangeOnBehalf(address(MyContract))` has
        // not yet been invoked by the user
        synthetix.exchangeOnBehalf(user, src, amount, dest);

        // Note: due to Fee Reclamation in SIP-37, the following actions will fail if attempted in the
        // same block (the waiting period for dest must first expire)
          // synthetixResolver.getSynth(dest).transferFrom(user, address(0), 1e12)
          // synthetix.exchangeOnBehalf(user, dest, 1e12, "sBTC");
          // synthetixResolver.getAddress("Exchanger").settle(user, dest)
    }
}