Example

This example will show an actual example of an arbitrage message using the White Whale Flashloans. Obviously this example was succesfully executed in the past and therefore won't work anymore and is only used as a reference. The whole message looks like this:

{
  "flash_loan": {
    "msgs": [
      {
        "wasm": {
          "execute": {
            "msg": "eyJzd2FwIjp7Im1heF9zcHJlYWQiOiIwLjA1Iiwib2ZmZXJfYXNzZXQiOnsiYW1vdW50IjoiMjk4MzAzOTIiLCJpbmZvIjp7Im5hdGl2ZV90b2tlbiI6eyJkZW5vbSI6InVsdW5hIn19fSwiYmVsaWVmX3ByaWNlIjoiMC42NDk5NTcifX0=",
            "funds": [
              {
                "denom": "uluna",
                "amount": "29830392"
              }
            ],
            "contract_addr": "terra1fd68ah02gr2y8ze7tm9te7m70zlmc7vjyyhs6xlhsdmqqcjud4dql4wpxr"
          }
        }
      },
      {
        "wasm": {
          "execute": {
            "msg": "eyJzd2FwIjp7Im1heF9zcHJlYWQiOiIwLjA1Iiwib2ZmZXJfYXNzZXQiOnsiYW1vdW50IjoiNDU4OTU5NjciLCJpbmZvIjp7Im5hdGl2ZV90b2tlbiI6eyJkZW5vbSI6ImliYy9CMzUwNEUwOTI0NTZCQTYxOENDMjhBQzY3MUE3MUZCMDhDNkNBMEZEMEJFN0M4QTVCNUEzRTJERDkzM0NDOUU0In19fSwiYmVsaWVmX3ByaWNlIjoiMC4wNjUzMTYifX0=",
            "funds": [
              {
                "denom": "ibc/B3504E092456BA618CC28AC671A71FB08C6CA0FD0BE7C8A5B5A3E2DD933CC9E4",
                "amount": "45895967"
              }
            ],
            "contract_addr": "terra1w579ysjvpx7xxhckxewk8sykxz70gm48wpcuruenl29rhe6p6raslhj0m6"
          }
        }
      },
      {
        "wasm": {
          "execute": {
            "msg": "eyJzZW5kIjp7ImFtb3VudCI6IjcwMjY3MDc3NyIsImNvbnRyYWN0IjoidGVycmExZTZ0MzdmZ2preHJ6ZHgyczk1ZnlxNmpkcmE1czgyNzIwdmh0bXh2eDR5aGN2bnNyZXk0c3NtcnlhNiIsIm1zZyI6ImV5SnpkMkZ3SWpwN0ltSmxiR2xsWmw5d2NtbGpaU0k2SWpJekxqSTJOall5T0NJc0ltMWhlRjl6Y0hKbFlXUWlPaUl3TGpBd01EVWlmWDA9In19",
            "funds": [],
            "contract_addr": "terra1nsuqsk6kh58ulczatwev87ttq2z6r3pusulg9r24mfj2fvtzd4uq3exn26"
          }
        }
      }
    ],
    "assets": [
      {
        "info": {
          "native_token": {
            "denom": "uluna"
          }
        },
        "amount": "29830392"
      }
    ]
  }
}

As described in Calling Flashloans, the asset field holds a list of assets we want to borrow from one of the White Whale vaults. In this example, we wanted to borrow 29830392uluna, which is ~29.8 luna. After getting the flashloan from the luna vault in this case, the contract executes the messages in the msgs field sequentially.

First message

{
        "wasm": {
          "execute": {
            "msg": "eyJzd2FwIjp7Im1heF9zcHJlYWQiOiIwLjA1Iiwib2ZmZXJfYXNzZXQiOnsiYW1vdW50IjoiMjk4MzAzOTIiLCJpbmZvIjp7Im5hdGl2ZV90b2tlbiI6eyJkZW5vbSI6InVsdW5hIn19fSwiYmVsaWVmX3ByaWNlIjoiMC42NDk5NTcifX0=",
            "funds": [
              {
                "denom": "uluna",
                "amount": "29830392"
              }
            ],
            "contract_addr": "terra1fd68ah02gr2y8ze7tm9te7m70zlmc7vjyyhs6xlhsdmqqcjud4dql4wpxr"
          }
        }
      },

Which, as we can see, uses the borrowed assets from the assets field in the funds field. This is an important detail of designing the message. Next, the contract_addr field is filled with the AMM pool address of the pool we wanted to swap this luna on, namely terra1fd68ah02gr2y8ze7tm9te7m70zlmc7vjyyhs6xlhsdmqqcjud4dql4wpxr, which is an AMM pool that holds luna and axlUSDC. Lastly, the msg field is filled with the base64 encoded message to be executed, if we decode it (using https://base64.guru/converter/decode/ascii for example) we can see it says:

{
   "swap":{
      "max_spread":"0.05",
      "offer_asset":{
         "amount":"29830392",
         "info":{
            "native_token":{
               "denom":"uluna"
            }
         }
      },
      "belief_price":"0.649957"
   }
}

Second message

{
        "wasm": {
          "execute": {
            "msg": "eyJzd2FwIjp7Im1heF9zcHJlYWQiOiIwLjA1Iiwib2ZmZXJfYXNzZXQiOnsiYW1vdW50IjoiNDU4OTU5NjciLCJpbmZvIjp7Im5hdGl2ZV90b2tlbiI6eyJkZW5vbSI6ImliYy9CMzUwNEUwOTI0NTZCQTYxOENDMjhBQzY3MUE3MUZCMDhDNkNBMEZEMEJFN0M4QTVCNUEzRTJERDkzM0NDOUU0In19fSwiYmVsaWVmX3ByaWNlIjoiMC4wNjUzMTYifX0=",
            "funds": [
              {
                "denom": "ibc/B3504E092456BA618CC28AC671A71FB08C6CA0FD0BE7C8A5B5A3E2DD933CC9E4",
                "amount": "45895967"
              }
            ],
            "contract_addr": "terra1w579ysjvpx7xxhckxewk8sykxz70gm48wpcuruenl29rhe6p6raslhj0m6"
          }
        }
      }

This second message is send to the contract_addr "terra1w579ysjvpx7xxhckxewk8sykxz70gm48wpcuruenl29rhe6p6raslhj0m6" which is an AMM pool that holds axlUSDC and ASTRO (Astroport's protocol token). Since axlUSDC is an IBC-token and therefore treated as a native_token, the overall message looks a whole lot like the first message of the msgs field, it just has different entries for the required fields. Please note that the amount of uaxlUSDC used in this second swap (45895967) is precalculated, we have to enter this value ourselves and the contract does not derive it for us.

Third message

The third and last message from this specific example holds another swap on an AMM pool, namely the ASTRO-Luna pool.

{
        "wasm": {
          "execute": {
            "msg": "eyJzZW5kIjp7ImFtb3VudCI6IjcwMjY3MDc3NyIsImNvbnRyYWN0IjoidGVycmExZTZ0MzdmZ2preHJ6ZHgyczk1ZnlxNmpkcmE1czgyNzIwdmh0bXh2eDR5aGN2bnNyZXk0c3NtcnlhNiIsIm1zZyI6ImV5SnpkMkZ3SWpwN0ltSmxiR2xsWmw5d2NtbGpaU0k2SWpJekxqSTJOall5T0NJc0ltMWhlRjl6Y0hKbFlXUWlPaUl3TGpBd01EVWlmWDA9In19",
            "funds": [],
            "contract_addr": "terra1nsuqsk6kh58ulczatwev87ttq2z6r3pusulg9r24mfj2fvtzd4uq3exn26"
          }
        }
      }

A very important distinction to make here is that we do not fill the funds field. We are swapping ASTRO (which we obtained from message 2) into Luna (which we borrowed), means our cyclic arbitrage is complete and we can use the obtained Luna from this third swap to repay the borrowed Luna amount with the flashloan (the contract does this for us). However, the ASTRO token we are swapping for Luna is not a native_token but rather a CW-20 token. This unfortunately requires a different message. So if we decode the msg field here we see:

{
   "send":{
      "amount":"702670777",
      "contract":"terra1e6t37fgjkxrzdx2s95fyq6jdra5s82720vhtmxvx4yhcvnsrey4ssmrya6",
      "msg":"eyJzd2FwIjp7ImJlbGllZl9wcmljZSI6IjIzLjI2NjYyOCIsIm1heF9zcHJlYWQiOiIwLjAwMDUifX0="
   }
}

Which is a so-called "SendMsg" and it holds its own msg field, which is decoded into:

{
   "swap":{
      "belief_price":"23.266628",
      "max_spread":"0.0005"
   }
}

Important: when swapping a CW20 token, the contract_addr field we use in our messages is the CW20 token address of this specific token, in our example: terra1nsuqsk6kh58ulczatwev87ttq2z6r3pusulg9r24mfj2fvtzd4uq3exn26. This address is not the AMM pool address!

So where do we find the AMM pool address we want to swap this token on? Well, its baked in the "SendMsg" namely the `contract` field.

Executing the message

This section is only necessary if you are trying to use the flashloans via some blockchain client and are not using our provided flashloan page.

Now that we obtained the full flashloan message, we can send it to the Flashloan router contract, the address of this contract on specific chains can be found here. We send it by wrapping it in a MsgExecuteContract type, which is a wasm-type well known within the cosmos ecosystem. Every client that interacts with wasm-contracts (which the flashloan router contract is) holds a method to send this MsgExecuteContract to a specific contract. It roughly looks like this:

/** MsgExecuteContract submits the given message data to a smart contract */
export interface MsgExecuteContract {
    /** Sender is the that actor that signed the messages */
    sender: string;
    /** Contract is the address of the smart contract */
    contract: string;
    /** Msg json encoded message to be passed to the contract */
    msg: Uint8Array;
    /** Funds coins that are transferred to the contract on execution */
    funds: Coin[];
}

Our designed flashloan message goes in the msg field and has to be properly encoded. If you have trouble finding the right encoding, contact us and we are happy to help you out!