Modify Order

Description

Modify an active order's price and quantity. Internally implemented as cancel-and-resubmit: the previous resting order is removed from the book, margin freezing is recomputed for the new size, and a fresh order is queued under the same orderId (so callers don't see the id change). The updateTime timestamp is refreshed. Already-filled quantity is preserved — modify is rejected with -1102 (New quantity ... cannot be smaller than already-filled ...) if quantity < executedQty.

Only resting LIMIT orders can be modified. Any other order type — and any order that is no longer in NEW / PARTIALLY_FILLED status — is rejected with -2013 (Order does not exist or cannot be modified.).

HTTP Request

PUT /fapi/v1/order (HMAC SHA256)

Request Parameters

Name	Type	Required	Description
symbol	STRING	YES	Trading pair
orderId	STRING	NO	System order ID (UUID)
origClientOrderId	STRING	NO	User-defined order ID
side	ENUM	NO	Order side: BUY, SELL. Optional — the side of an order is immutable; if sent, it must match the resting order's side, otherwise -1102.
quantity	DECIMAL	YES	New total order quantity (must be ≥ already-filled quantity).
price	DECIMAL	YES	New limit price.
recvWindow	LONG	NO	Accepted but ignored — the server enforces a fixed ±60 second timestamp window instead.
timestamp	LONG	YES	Timestamp

Both quantity and price are required. Either orderId or origClientOrderId must be sent to identify the target order.

Response Example

{
    "orderId": "3fa42833-9508-4061-8d80-b68563dcd521",
    "symbol": "BTCUSDT",
    "status": "NEW",
    "clientOrderId": "testOrderModify1",
    "price": "60000",
    "avgPrice": "0",
    "origQty": "0.1",
    "executedQty": "0",
    "cumQuote": "0",
    "timeInForce": "GTC",
    "type": "LIMIT",
    "reduceOnly": false,
    "side": "BUY",
    "positionSide": "BOTH",
    "stopPrice": "0",
    "workingType": "CONTRACT_PRICE",
    "priceProtect": false,
    "origType": "LIMIT",
    "updateTime": 1774330265238,
    "time": 1774330191022
}

Errors

Code	Cause
-1100	quantity / price not positive or unparsable
-1102	quantity below already-filled amount, or side does not match the resting order
-2011	Order raced out of the matching engine (filled / cancelled mid-flight) — cannot modify
-2013	Order does not exist, is not a LIMIT order, or is not in a modifiable status
-2019	Margin insufficient for the enlarged order

Code Examples

cURL

API_KEY="your_api_key"
API_SECRET="your_api_secret"
TIMESTAMP=$(date +%s%3N)
BODY='{"symbol":"BTCUSDT","orderId":"3fa42833-9508-4061-8d80-b68563dcd521","side":"BUY","quantity":"0.1","price":"60000"}'
SIGNATURE=$(echo -n "timestamp=${TIMESTAMP}${BODY}" | openssl dgst -sha256 -hmac "${API_SECRET}" | awk '{print $2}')

curl -s -X PUT \
  -H "X-MBX-APIKEY: ${API_KEY}" \
  -H "Content-Type: application/json" \
  -d "${BODY}" \
  "https://api.prex.world/fapi/v1/order?timestamp=${TIMESTAMP}&signature=${SIGNATURE}"

Python

import time, hmac, hashlib, requests, json

API_KEY = "your_api_key"
API_SECRET = "your_api_secret"
BASE_URL = "https://api.prex.world"

def sign(msg: str) -> str:
    return hmac.new(API_SECRET.encode(), msg.encode(), hashlib.sha256).hexdigest()

def signed_put(path, body={}):
    ts = int(time.time() * 1000)
    qs = f"timestamp={ts}"
    body_str = json.dumps(body, separators=(',', ':'))
    sig = sign(qs + body_str)
    return requests.put(
        f"{BASE_URL}{path}?timestamp={ts}&signature={sig}",
        data=body_str,
        headers={"X-MBX-APIKEY": API_KEY, "Content-Type": "application/json"},
    )

# Modify an existing order's quantity and price
resp = signed_put("/fapi/v1/order", body={
    "symbol": "BTCUSDT",
    "orderId": "3fa42833-9508-4061-8d80-b68563dcd521",
    "side": "BUY",
    "quantity": "0.1",
    "price": "60000",
})
print(resp.json())