CEX.IO Trading Bot in Python

This guide shows how to build a CEX.IO trading bot in Python with LumiBot, for both AI agent trading and algorithmic trading. LumiBot connects to CEX.IO through CCXT, the open source library that talks to more than 100 crypto exchanges. You will create a CEX.IO account and API key, connect it, and run two examples: a simple algorithmic trading bot and an agentic trading bot where an AI agent makes the calls.

CEX.IO at a glance

CCXT exchange id

cex

Markets

Spot

Testnet (sandbox)

No

Credentials

API key, API secret

Live data streams

prices, order book, trades, candles, your orders, your balance

CCXT request spacing

about 300 ms between requests

Official site

https://cex.io

API docs

https://trade.cex.io/docs/

Fees

https://cex.io/fee-schedule

What is CEX.IO?

CEX.IO is a crypto exchange that has run since 2013. Its Spot Trading platform has REST and WebSocket APIs for placing and canceling orders and reading market data.

Sign up for CEX.IO

  1. Create a CEX.IO account and finish the identity verification CEX.IO asks for.

  2. Turn on two-factor authentication. CEX.IO asks for a 2FA code when you create an API key.

  3. CEX.IO has no testnet, so plan to test with a very small amount.

Open a CEX.IO account

Create a CEX.IO API key

  1. Log in to CEX.IO Spot Trading, click your name in the upper right corner, choose Profile and open API Keys Management.

  2. Click + NEW API KEY and give the key a name.

  3. Choose the permissions (see below) and add your bot’s IP address to the IP whitelist.

  4. Click Create API Key and confirm with your 2FA code.

  5. Save the API Secret from the pop-up right away. CEX.IO will not show it again.

  6. Click Activate next to the new key and confirm with the code sent to your email. A new key does not work until you activate it.

Which permissions to turn on: Turn on Read and Trade. Read lets the bot see your balances and orders, and Trade lets it place and cancel orders. Leave Funds Internal and Funds Wallet (shown as Funds External in the key list) off. A trading bot does not need to move money.

Warning

Never turn on withdrawals for a CEX.IO trading bot key. Bind the key to your server’s IP address when CEX.IO lets you, keep the secret out of your code and out of Git, and delete the key if it ever leaks.

Connect CEX.IO to LumiBot

The simplest way: put these lines in a .env file next to your strategy. LumiBot loads the file, sees TRADING_BROKER=cex and connects to CEX.IO for you, so your strategy needs no broker code.

TRADING_BROKER=cex
CEX_API_KEY=your_apiKey
CEX_API_SECRET=your_secret

LumiBot reads exactly the fields CCXT needs for CEX.IO (apiKey, secret). If one is missing, LumiBot stops at start-up and names the variable you still need.

You can also build the broker in code. This is handy when one script talks to more than one exchange, or when you need extra CCXT options. The keys in the config are CCXT’s own credential names for CEX.IO:

import os

CEX_CONFIG = {
    "exchange_id": "cex",
    "apiKey": os.environ.get("CEX_API_KEY"),
    "secret": os.environ.get("CEX_API_SECRET"),
    "sandbox": False,  # no sandbox for this exchange
}

from lumibot.brokers import Ccxt

broker = Ccxt(CEX_CONFIG)
# then: MyStrategy(broker=broker, ...)

Either way, LumiBot turns on CCXT’s built-in rate limiting for you.

Testing on CEX.IO

CEX.IO has no sandbox, and CCXT lists no test URL for it, so test with a very small amount. With environment variables, leave CEX_SANDBOX unset. In a code config, set "sandbox": False.

Algorithmic trading example: a simple CEX.IO bot

This bot buys about 50 USDT of BTC on CEX.IO once and then holds it. It is a starting point to check that your keys, balances and orders work. If the exchange’s minimum order is larger, raise the amount.

from lumibot.entities import Asset
from lumibot.strategies import Strategy


class CexBuyOnce(Strategy):
    """Buy a small amount of BTC once, then hold it."""

    def initialize(self):
        self.sleeptime = "1H"
        self.set_market("24/7")  # crypto trades all day, every day

    def on_trading_iteration(self):
        coin = Asset("BTC", asset_type=Asset.AssetType.CRYPTO)
        if self.get_position(coin) is not None:
            return  # already holding BTC
        price = self.get_last_price(coin, quote=self.quote_asset)
        if price:
            quantity = round(50 / price, 6)  # about 50 USDT worth
            order = self.create_order(coin, quantity, "buy", quote=self.quote_asset)
            self.submit_order(order)


if __name__ == "__main__":
    # LumiBot reads TRADING_BROKER and the keys from your .env file.
    strategy = CexBuyOnce(quote_asset=Asset("USDT", asset_type=Asset.AssetType.CRYPTO))
    strategy.run_live()

Agentic trading example: an AI agent that trades on CEX.IO

Agentic trading means an AI agent reads the market and decides what to do. In this example one LumiBot agent looks at prices and your CEX.IO account, then places the orders itself. There is no Python logic in between: you set the rules in plain English in the prompt, such as what it may trade and how big each order can be. This follows the same pattern as LumiBot’s AI trading team examples.

from lumibot.entities import Asset
from lumibot.strategies import Strategy


class CexAITrader(Strategy):
    """One AI agent researches the market and places the trades itself."""

    def initialize(self):
        self.sleeptime = "4H"
        self.set_market("24/7")
        self.agents.create(
            name="trader",
            model="openai/gpt-6-luna",
            reasoning_effort="high",
            allow_trading=True,
            system_prompt=(
                "You manage a small crypto account on CEX.IO. "
                "You may trade BTC and ETH against USDT (asset_type 'crypto', quote_symbol 'USDT'), or hold cash. "
                "Before every order, call account_portfolio, account_positions and "
                "market_last_price for that exact symbol in the same run. "
                "Keep each order under 10% of the account value. "
                "Explain each decision in one short paragraph."
            ),
        )

    def on_trading_iteration(self):
        self.agents["trader"].run(
            task_prompt="Review recent BTC/USDT and ETH/USDT prices and your current holdings, then decide whether to buy, sell or hold.",
            context={"exchange": "CEX.IO", "quote": "USDT", "date": self.get_datetime().isoformat()},
        )


if __name__ == "__main__":
    # LumiBot reads TRADING_BROKER and the keys from your .env file.
    strategy = CexAITrader(quote_asset=Asset("USDT", asset_type=Asset.AssetType.CRYPTO))
    strategy.run_live()

The agent needs a model key such as OPENAI_API_KEY in your environment. See the AI agents quickstart for models, tools and memory.

What you can trade on CEX.IO through CCXT

Market

Listed by CCXT

Spot

Yes

Margin

No

Perpetual swaps

No

Dated futures

No

Options

No

CCXT lists these order features for CEX.IO: market orders, limit orders, stop orders, editing open orders, canceling orders.

CEX.IO tips

  • If you edit a key’s permissions or IP whitelist later, CEX.IO turns the key off. Click Activate and confirm by email again, or your bot will stop working.

  • If you leave the IP whitelist blank, the key works from any IP address. Adding your bot’s IP is safer.

  • CEX.IO Spot Trading supports sub-accounts (five by default, more on request). A sub-account per bot keeps bot trades apart from your own.

  • CEX.IO lists BTC against several quote currencies, including USD, EUR, GBP, USDT and USDC. Use the quote currency you actually hold.

Frequently asked questions

Can I build a CEX.IO trading bot in Python?

Yes. Install LumiBot (pip install lumibot), set your CEX.IO keys and use the cex CCXT exchange id as shown above.

Does CEX.IO have a testnet?

No testnet is set up for CEX.IO in LumiBot. Start with a small amount, and in a code config set "sandbox": False.

Which API permissions does a CEX.IO bot need?

Turn on Read and Trade. Read lets the bot see your balances and orders, and Trade lets it place and cancel orders. Leave Funds Internal and Funds Wallet (shown as Funds External in the key list) off. A trading bot does not need to move money.

Can an AI agent trade on CEX.IO by itself?

Yes. The agentic example above gives one agent permission to trade. You control what it may trade and how much through its prompt.

Can I trade CEX.IO perpetual futures with LumiBot?

CCXT does not list perpetual swaps for CEX.IO, so use spot markets.

Is LumiBot free?

Yes. LumiBot is open source on GitHub at https://github.com/Lumiwealth/lumibot. You pay only your exchange’s trading fees and, for AI agents, your model provider.

Run it in the cloud with BotSpot

Do not want to keep a computer running for your CEX.IO bot? BotSpot is the hosted home for LumiBot strategies and AI trading agents: build with AI, backtest, connect a broker, and watch every trade with logs and alerts.

Try BotSpot

Sources