使用Bybit API进行BTC/USDT衍生品交易时遇qty invalid错误求助

问题描述 #

我尝试通过Bybit API购买最小量BTC，已输入平台要求的最小下单量（0.001 BTC），且账户USDT余额充足（当前余额99.97 USDT），但下单时持续返回错误：params error: qty invalid。

运行日志 #

Starting USDT balance: 99.97 No BTC in the account. Buying 0.001 BTC... Placing market buy order for 0.00100000 BTC at 28254.80 USDT/BTC Order response: {'ret_code': 10001, 'ret_msg': 'params error: qty invalid', 'result': {}, 'ext_code': '', 'ext_info': '', 'time_now': '1680641484.301085', 'rate_limit_status': 99, 'rate_limit': 100, 'rate_limit_reset_ms': 1680641484300}

我的Python代码 #

import requests
import time
import hmac
import hashlib
from urllib.parse import urlencode

# API keys
API_KEY = 'API KEY'
API_SECRET = 'API SECRET'

# Base URLs
BYBIT_BASE_URL = 'https://api.bybit.com'

# Constants
SYMBOL = 'BTCUSDT'
ORDER_TYPE = 'Market'
FIXED_ORDER_QTY_BTC = 0.001
QUANTITY_STEP_SIZE = 0.001

def generate_signature(secret, params):
    query_string = urlencode(sorted(params.items()))
    hmac_sha256 = hmac.new(secret.encode('utf-8'), query_string.encode('utf-8'), hashlib.sha256)
    return hmac_sha256.hexdigest()

def get_balance(coin):
    timestamp = int(time.time() * 1000)
    params = {
        'api_key': API_KEY,
        'timestamp': timestamp,
        'coin': coin
    }
    params['sign'] = generate_signature(API_SECRET, params)
    url = f"{BYBIT_BASE_URL}/v2/private/wallet/balance"
    response = requests.get(url, params=params)
    return response.json()

def place_order(side, qty, order_type):
    timestamp = int(time.time() * 1000)
    params = {
        'api_key': API_KEY,
        'timestamp': timestamp,
        'symbol': SYMBOL,
        'side': side,
        'order_type': order_type,
        'qty': qty,
        'time_in_force': 'GoodTillCancel',
        'reduce_only': False
    }
    params['sign'] = generate_signature(API_SECRET, params)
    url = f"{BYBIT_BASE_URL}/v2/private/order/create"
    response = requests.post(url, data=params)
    return response.json()

def get_ticker_price(symbol):
    url = f"{BYBIT_BASE_URL}/v2/public/tickers?symbol={symbol}"
    response = requests.get(url)
    return response.json()

def main():
    # Get current USDT balance
    usdt_balance = float(get_balance('USDT')['result']['USDT']['available_balance'])
    print(f"Starting USDT balance: {usdt_balance:.2f}")

    # Check if BTC balance is zero
    btc_balance = float(get_balance('BTC')['result']['BTC']['available_balance'])
    if btc_balance == 0:
        print(f"No BTC in the account. Buying {FIXED_ORDER_QTY_BTC} BTC...")
        ticker_price = float(get_ticker_price(SYMBOL)['result'][0]['last_price'])
        order_qty = round(FIXED_ORDER_QTY_BTC / QUANTITY_STEP_SIZE) * QUANTITY_STEP_SIZE
        print(f"Placing market buy order for {order_qty:.8f} BTC at {ticker_price:.2f} USDT/BTC")
        response = place_order('Buy', order_qty, ORDER_TYPE)
        print(f"Order response: {response}")

    while True:
        # Get current BTC balance
        btc_balance = float(get_balance('BTC')['result']['BTC']['available_balance'])
        if btc_balance >= order_qty:
            print(f"Bought {order_qty:.8f} BTC")
            break
        else:
            print("Waiting for BTC to be bought...")
            time.sleep(10)

        # Get updated USDT balance
    usdt_balance = float(get_balance('USDT')['result']['USDT']['available_balance'])
    print(f"Updated USDT balance: {usdt_balance:.2f}")


if __name__ == '__main__':
    main()

问题原因 #

你使用的/v2/private/order/create是合约交易接口，该接口中qty参数的单位不是BTC，而是「合约张数」（BTCUSDT合约每张对应0.001 BTC）。你直接传入0.001作为qty，会被识别为0.001张，不符合合约最小下单张数（通常为1张）的要求，因此触发参数错误。

如果你的需求是现货交易，则需要使用现货专用API接口，而非合约接口。

解决方案 #

方案1：进行合约交易（USDT永续） #

将qty改为整数1（对应0.001 BTC），因为合约以「张数」为单位：

def place_order(side, qty, order_type):
    timestamp = int(time.time() * 1000)
    params = {
        'api_key': API_KEY,
        'timestamp': timestamp,
        'symbol': SYMBOL,
        'side': side,
        'order_type': order_type,
        'qty': 1,  # 修改为1张，对应0.001 BTC
        'time_in_force': 'GoodTillCancel',
        'reduce_only': False
    }
    params['sign'] = generate_signature(API_SECRET, params)
    url = f"{BYBIT_BASE_URL}/v2/private/order/create"
    response = requests.post(url, data=params)
    return response.json()

方案2：进行现货交易 #

替换为现货专用接口/spot/v1/order，并调整参数格式：

def place_order(side, qty, order_type):
    timestamp = int(time.time() * 1000)
    params = {
        'api_key': API_KEY,
        'timestamp': timestamp,
        'symbol': SYMBOL,
        'side': side.upper(),
        'type': order_type.upper(),
        'qty': str(qty),  # 现货接口要求qty为字符串格式
        'timeInForce': 'GTC'  # 现货接口参数名为timeInForce，而非time_in_force
    }
    params['sign'] = generate_signature(API_SECRET, params)
    url = f"{BYBIT_BASE_URL}/spot/v1/order"
    response = requests.post(url, data=params)
    return response.json()

现货交易的最小下单量确实是0.001 BTC，你的FIXED_ORDER_QTY_BTC = 0.001符合要求。

额外检查点 #

• 确认API密钥权限：现货交易需开启现货权限，合约交易需开启合约权限；
• 检查参数大小写：Bybit部分API参数区分大小写，比如现货接口的timeInForce不能写成time_in_force。

内容的提问来源于stack exchange，提问作者Daan