Tracking orders on 0x network

Question

How are the various 0x network order trackers sourcing on-chain settlement data?

My first assumption was that they were utilising the Etherscan API, however Etherscan have their own tracker, found at https://etherscan.io/dextracker , which appears to have more complete transactional data than others such as https://0xtracker.com/ and http://0xtrades.info/ .

All three of the above have inconsistent data, which leads me to believe that there is no current best practice.

From a given list of relayers, I'm trying to obtain the order JSON for each transaction as following:

{
  "maker": {
    "token": {
      "address": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
      "name": "Wrapped Ether",
      "symbol": "WETH",
      "decimals": 18
    },
    "address": "0xa793f13c7c7d38b2ffb27c5273edbd0245adbe76",
    "amount": "334823067048678893",
    "feeAmount": "0"
  },
  "taker": {
    "token": {
      "address": "0x107c4504cd79c5d2696ea0030a8dd4e92601b82e",
      "name": "Bloom Token",
      "symbol": "BLT",
      "decimals": 18
    },
    "address": "",
    "amount": "418006325903469279650",
    "feeAmount": "0"
  },
  "signature": {
    "v": 27,
    "r": "0x48a7e06a617bd10ea3684d4f40a9e2b1167d3fd003245dd096adbad53e11195a",
    "s": "0x6c3c9df27ffd23371a35f7b6f0928031df1ace65f04de1023da4e05ffd31adb2",
    "hash": "0x52c77348c40f58fcd1e48b5fa91322ca515a7824b834dc9fcdb25a65ac76e96b"
  },
  "expiration": "1520170848",
  "feeRecipient": "0xa258b39954cef5cb142fd567a46cddb31a670124",
  "salt": "72248519509688682556724797082899905741793832544995882654354657068693442284506",
  "exchangeContract": "0x12459c951127e0c374ff9105dda097662a027093",
  "networkId": 1
}

Answer 1

Tracking is usually performed by listening for the trade events originating from the 0x contracts, see here for the events https://protocol.0x.org/en/latest/basics/events.html.

You could also consume the 0xTracker API, https://docs.0xtracker.com/api-reference/endpoints.