The matching engine codes and their descriptions are outlined here

REQUEST

HEADER PARAMS


msg_type string required Message type: `add_order`
id number required The ID of the request. This is returned in the response header.
version integer required Version number:`1`

BODY PARAMS


account_id string required Account address which is placing the order.
instrument_id string required The instrument to buy or sell.
size string required Size of position to trade in the underlying asset.
side string required Can be `buy` or `sell`.
order_type string required Can be `limit`, `market`, `take_profit`, or `stop` .
time_in_force string required Can be one of `gtc` (Good till cancelled), `gte` (Good till expiration), `ioc` (Immediate or cancel), or `fok` (Fill-or-Kill).
execution_type string Can be `post_only` or `allow_cross`. `post_only` is only supported for `limit` orders.
signature string required Signed order fields which are submitted to smart contracts for processing.
client_order_id string ID assigned to the order by the client. This must be unique per-account. Will be set automatically to the exchange’s unique `order_id` if absent.
limit_price string Limit price for the order. If this field is absent, null, or zero for `take_profit` and `stop` orders, the order will execute at market once the `trigger_price` is reached. This field must be absent, null or zero for `market` orders.
expiration number Time that order will explicitly be canceled, in UNIX epoch seconds. For orders which do not have time-in-force `gte`, this field must be absent or explicitly set to null or zero.
nonce string required Used to make orders with otherwise identical signed fields unique. See nonce section in glossary for specific requirements.
reduce_only boolean If `true`, this order will only reduce the size of an open position. Always `true` for `take_profit` orders.
trigger_price string The reference price at which the order will become active. Required for `take_profit` and `stop` orders. Ignored for other order types.

Example

[
  {
    "msg_type":"add_order",
    "id": 1002,
    "version": 1
  },
  {
    "account_id":"0x9f58498b98348b9BFbE53F0E18AA818a4Be0aE49",
    "instrument_id": "ETH-PERPETUAL",
    "size": "1",
    "size": "buy",
    "order_type": "limit",
    "time_in_force": "gtc",
    "execution_type": "allow_cross",
    "limit_price": "4000",
    "expiration": 0,
    "nonce": "7433990883764493008",
    "signature": "0xf86ea8c7f9a8e93f91b292b1e6ff3e0bb9b12f3aeb9ed32f3450fbbf1a2a5d181b7aef913589aa45d6d0bdf5c3085f8a3103a1e2fa1572bf12a55a8d7408df631c",
    "reduce_only": false
  }
]

RESPONSE

account_id string
The account address which placed the order.

transaction_ts string
The time the order was received by the system in UNIX epoch nanoseconds.

avg_execution_price string
The average execution price of the fills, if any.

client_order_id string
The client-assigned order ID. Set automatically to order_id if absent.

execution_type string
The execution type of the order. Can be post_only or allow_cross.

expiration string
The expiration time of the order in UNIX epoch seconds.

fillsarray of objects


transaction_ts string The time the fill occurred in UNIX epoch nanoseconds.
fill_price string The price of the fill.
fill_size string The size of the fill.
fill_total_fee string The total fee of the fill.
is_maker boolean Whether the fill was a maker order.
is_liquidation boolean Whether the fill was a liquidation.
trade_pnl string The realized profit and loss of the fill.
market_seqno string The market sequence number of the `fill`. A monotonic sequence number updated for each book event. e.g. a fill, cancel, etc.
trade_id string The unique ID of the trade.

initial_size string
The initial size of the order.

instrument_id string
The instrument of the order.

limit_price string
The limit price of the order.

status string
The status of the order.

cancel_reason string
The reason the order was canceled. Only included if the status is a cancel.

nonce string
An arbitrary number that can only be used once, used to ensure freshness of the order.

order_id string
The unique ID of the order.

order_type string
Can be limit, market, take_profit, or stop.

remaining_size string
The remaining unfilled portion of the order.

side string
The side of the order.

signature string
Signed order fields which are submitted to smart contracts for processing.

time_in_force string
The time in force of the order. Can be gtc, gte, ioc, or fok.

total_fill_size string
The total size of the fills.

total_fill_size string
The reason the order was canceled. Only included if the status is a cancel.

reduce_only boolean
Whether the order is reduce only.

trigger_price string
The trigger price of the order. Only present for take_profit and stop orders.

market_seqno string
The market sequence number of the new order. A monotonic sequence number updated for each book event. e.g. a fill, cancel, etc.

prev_order_type string
The original order type before it was triggered into a new state. This field will differ from order_type if the order transitioned to a different type upon triggering a condition (e.g., a stop order converting to a market order). If no such transition occurred, this field will match order_type.

Example

[
  {
    "msg_type":"add_order_response",
    "id": 1002,
    "version": 1
  },
  {
      "account_id": "0x9f58498b98348b9bfbe53f0e18aa818a4be0ae49",
      "transaction_ts": "1714441870685341751",
      "avg_execution_price": "3207.60",
      "client_order_id": "8524676410238383080",
      "execution_type": "allow_cross",
      "expiration": "1723081870",
      "fills": [
          {
              "transaction_ts": "1714441870686868798",
              "fill_price": "3207.6",
              "fill_size": "63.98",
              "fill_total_fee": "1.25",
              "is_maker": false,
              "is_liquidation": false,
              "trade_pnl": "20.01",
            	"market_seqno": 123457,
            	"trade_id": "11416748077714502636"
          }
      ],
      "initial_size": "63.98",
      "instrument_id": "ETH-PERPETUAL",
      "limit_price": "3208.87",
      "status": "full_fill",
      "nonce": "7433990883764493008",
      "order_id": "8524676410238383080",
      "order_type": "limit",
      "remaining_size": "0",
      "side": "buy",
      "signature": "0x8fdfb5a6f2fc9d25ff844d3ff3de0cc1f226c55cb9c632ff65f5532d6d1ea79f1f35f8ed588dcc2229b12165a2ca986fcde25aedf415adae0586823131db39741b",
      "time_in_force": "gtc",
      "total_fill_size": "63.98",
      "cancel_reason": "cancel_order", // Only incldued if status is a cancel (see glossary)
      "reduce_only": false,
      "market_seqno": 123456,
      "prev_order_type": "limit"
  }
]