Leverage not taken into account by Binance with CCXT in Python

Question

I got a little problem with ccxt on Python. I'm (trying) to code a trading bot which takes my custom tradingview signal. So I've been tinkering a little test code which opens a trade on testnet.binance with all my balance avalaible on BTC/USDT and with a certain leverage.

However, I have a problem with the leverage. Indeed, the code mentions a leverage of 10 and when I run the code locally, the UI mentions a leverage 'Isolated x10' but does not take it into account in the position size (see pictures). I have an approximate balance of 2600 USDT and a trade value of 2600 USDT.

Position through the code

Doing it manually via the UI and with 100% of my balance as well I do get a value of 26000 USDT in 'Isolated x10' which is expected.

Position through the UI

Do you have any idea why it takes into account the leverage but does not apply it to the position?

Here is the code:

import ccxt
import config

binaance = ccxt.binance({
    'enableRateLimit': True,  
    'options': {
        'defaultType': 'future',
    },
    'apiKey': config.API_KEY,  
    'secret': config.API_SECRET,
    'passphrase': config.PASSPHRASE,
})
binaance.set_sandbox_mode(True)
markets = binaance.load_markets()
symbol = 'BTC/USDT'
market = binaance.market(symbol)  

binaance.fapiPrivate_post_leverage({  
    'symbol': 'BTCUSDT',
    'leverage': 10,
})

def trade_crypto(request):
    
    free_balance = float(binaance.fetch_balance().get('USDT').get('free'))
    last_price = float(binaance.fetchTicker('BTC/USDT').get('last'))
    amount = free_balance / last_price  

    order = binaance.create_market_buy_order('BTC/USDT', amount)
    
    return order

Thank you for what you are doing here ! It helps a lot.

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[Edit 1 after @Sam answer]

Hey @Sam, first of all, thank you a lot for your answer. I didn't checked the margin on the right so thanks for that ! I was so sure that my amout calculations was right that I was not looking there. If I understood correctly the order has engaged 10% of my capital (260 USDT) to obtain 10x leverage with a trade value of 2600 USDT. So I made a change in the calculation which is:

leverage = 10

amount = (free_balance / last_price) * leverage

Result = (2600 / 38900) * 10 = approximately 0.6 btc

But then I got ''Insufficient Funds'' which is expected because it is trying to order with 26 000 USDT from my available balance, but the account only have 2 600.

So how to take in account the fact that the trade value must be 10x the value of my balance (=26 000 USDT) while engaging only 2600 USDT (which is possible trough the user interface)?

In this picture Buying trough the UI, we can see that with 10x leverage I can put my 2600 USDT available balance with a trade value of approximately 26 000 USD. I can't reproduce this behavior code wise.. Hope you or someone else can enlighten me aha.

Ps : I may not have mentioned it, but it concerns trading on futures perpetual contracts

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[Edit 2 after finding answer]

I finaly found the mistake. I had to multiply my 'amount' settings by the leverage to get the price in BTC with leverage and put only 99% of this amount because apparently, it can't put 100% of my balance (or maybe it can but I didn't found how to do it. Because with my method, the last price can vary and therefore change the amount which can't be bought or sold with my total balance).

I still have to find a way to put 100% of my balance (perhaps with a parameter that would not take into account the last price).

code modifications:

amount = ((free_balance / last_price) * 10 ) * 0.99

Answer 1

It is taking it into account, you can see that your margin is about 260 USDT and your size is 2600, you would need to place an order for 26000 USDT to use 10x leverage.

You're making an order for about 0.06 BTC, it's going to buy 0.06 BTC for you. At 10x leverage, that's going to cost you about 260 USDT, if you want to use your full 2600 USDT, you need to make an order for 0.6 BTC if you want to use the full amount of USDT that you have.