consenlabs / limit-order-trader

Tokenlon Limit Order

There are three steps for a market maker to integrate Tokenlon limit order.

• Fetch user orders
• Find a fillable order and get coordinator's signature
• Send a transaction to a specific blockchain

We only provide a testnet environment (Goerli) for now.

Fetch User Orders

You could acess user orders via the GET API below.

curl -X GET 'https://api.tokenlon.im/v5/limit-order/limitorder?chainId=1&status=pending,partialfilled'

Here is a order that a user(0xA307D607Ad04622fAF7F3A173314509dC69CAb67) wants to sell 12000000 0xa93Ef9215b907c19e739E2214e1AA5412a0401B5 tokens(6 decimals) for 10000000000000000 0xB4FBF271143F4FBf7B91A5ded31805e42b2208d6 tokens(18 decimals) and the fillable remain amount of the order in taker token units is 10000000000000000. So the pricing is 12 0xa93Ef9215b907c19e739E2214e1AA5412a0401B5 -> 0.01 0xB4FBF271143F4FBf7B91A5ded31805e42b2208d6

{
  "cancelledAt": "",
  "chainId": 1,
  "createdAt": "2022-12-29T03:50:57Z",
  "expiry": 1672372254,
  "id": 651,
  "maker": "0xA307D607Ad04622fAF7F3A173314509dC69CAb67",
  "makerSig": "0xce2d30b61b07a93162eeff015b6c8650874c8ac9fd083d96a02bd8f40ac392d816b43b71389ee2ee9a2cf0e809ee037074ded2fd493821fec84129caeef9e93b1c000000000000000000000000000000000000000000000000000000000000000002",
  "makerToken": "0xa93Ef9215b907c19e739E2214e1AA5412a0401B5",
  "makerTokenAmount": "12000000",
  "orderHash": "0x33474ad18cab17fd511db7261d12d48adfd324407103f2fd2bf4315c98a71e49",
  "remainQuota": "10000000000000000", // taker token units
  "salt": "81288522724654308173109929826343836162437203565474825798641954992826188088358",
  "status": "pending",
  "taker": "0x0000000000000000000000000000000000000000",
  "takerToken": "0xB4FBF271143F4FBf7B91A5ded31805e42b2208d6",
  "takerTokenAmount": "10000000000000000",
  "trades": [
    ...
  ],
  "updatedAt": "2022-12-29T04:08:37Z"
}

Each order contains a user target pricing and token addresses. market makers should check these pricing for themselves, in order to make sure they could profit from a order.

Get Coordinator's Signature

Once a market maker found a profitable order, it needs to create a trade request to monopolize the order. There's example code in the script.

export const createTrade = async (relayerAddress: string, limitOrder: LimitOrder, traderParams: TraderParams) => {
  const createTradeRequest = {
    chainId: chainId,
    tradeType: 'FilledByTrader',
    relayer: relayerAddress,
    orderHash: limitOrder.orderHash,
    traderParams: traderParams
  }

  try {
    const resp = await axios.post(createTradeAPI, createTradeRequest)
    const result = resp.data
    /*
    {
      sig: '0xadcaab370e1e2eaba02e491c834bc730d807ded0b8fc4c8a327febdc96d5c2783716bcced54be0125880008c0962dd7ad9cbb36f76124874479a892849beedd81b000000000000000000000000000000000000000000000000000000000000000002',
      expiry: 1672285977,
      salt: '53877022432961262906682897356647888273613148815032923035962179578712288650041'
    }
    */
    return result
  } catch (e) {
    console.error(e)
  }
}

Sending a Transaction

After getting a coordinator's signature, a market maker could send the transaction to fill the limit order. Check the code snippet to make a transaction calldata

export const makeCalldata = (
  limitOrder: LimitOrder,
  traderParams: TraderParams,
  coordinatorParams: CoordinatorParams
) => {
  const tradePayload = limitOrderContract.interface.encodeFunctionData('fillLimitOrderByTrader', [
    [
      limitOrder.makerToken,
      limitOrder.takerToken,
      limitOrder.makerTokenAmount,
      limitOrder.takerTokenAmount,
      limitOrder.maker,
      limitOrder.taker,
      limitOrder.salt,
      limitOrder.expiry,
    ],
    limitOrder.makerSig,
    [
      traderParams.taker,
      traderParams.recipient,
      traderParams.takerTokenAmount,
      traderParams.salt,
      traderParams.expiry,
      traderParams.takerSig,
    ],
    [
      coordinatorParams.sig,
      coordinatorParams.salt,
      coordinatorParams.expiry
    ],
  ])

  return tradePayload
}
...
const payload = makeCalldata(limitOrder, traderParams, coordinatorParams)
const data = await tokenlonContract.interface.encodeFunctionData('toLimitOrder', [ payload ])
// should set a proper gas price in a production environment
const suggestedGasPrice = ethers.utils.parseUnits('10', 'gwei').toString()
const txRequest: TransactionRequest = {
  data: data,
  from: takerWallet.address,
  to: tokenlonContract.address,
  value: '0x0',
  // the gas fee would also be part of the market maker's costs, should adjust the gas fee to maintain the order profits
  gasPrice: ethers.BigNumber.from(suggestedGasPrice.toString()),
  gasLimit: 3000000
}
console.log(txRequest)
const tx = await wallet.sendTransaction(txRequest)
console.log(tx)
const receipt = await tx.wait()
console.log(receipt)

Running tests

The script itself would send a new Tokenlon limit order to Tokenlon service, and fill the limit order right away in a forked mainnet environment.

npx hardhat test test/fillLimitOrderByTrader.ts