Polymarket API Python Guide: Build Your Own Trading Bot

from py_clob_client.client import ClobClient

# Read-only client - no auth needed
client = ClobClient("https://clob.polymarket.com")

# Fetch markets
markets = client.get_simplified_markets()
print(markets)

from py_clob_client.client import ClobClient

# Trading client - requires private key
client = ClobClient(
    host="https://clob.polymarket.com",
    key="YOUR_PRIVATE_KEY",
    chain_id=137,  # Polygon mainnet
    signature_type=2,  # Proxy wallet
    funder="YOUR_PROXY_ADDRESS"
)

# Create/derive API credentials
creds = client.create_or_derive_api_creds()
client.set_api_creds(creds)

# Get all markets
markets = client.get_simplified_markets()

# Get specific market by condition ID
market = client.get_market("CONDITION_ID")

# Get orderbook for a token
book = client.get_order_book("TOKEN_ID")
print(f"Best bid: {book['bids'][0]}")
print(f"Best ask: {book['asks'][0]}")

# Get midpoint price
mid = client.get_midpoint("TOKEN_ID")
print(f"Midpoint: {mid}")

from py_clob_client.clob_types import OrderArgs, OrderType
from py_clob_client.order_builder.constants import BUY, SELL

# Create a buy order
order_args = OrderArgs(
    price=0.45,        # Price per share
    size=100.0,        # Number of shares
    side=BUY,          # BUY or SELL
    token_id="TOKEN_ID"
)

# Sign the order
signed_order = client.create_order(order_args)

# Submit the order
resp = client.post_order(signed_order, OrderType.GTC)
print(f"Order ID: {resp['orderID']}")

from py_clob_client.clob_types import MarketOrderArgs

# Create a market buy order
mo_args = MarketOrderArgs(
    token_id="TOKEN_ID",
    amount=25.0,       # Dollar amount to spend
    side=BUY
)

signed_order = client.create_market_order(mo_args)
resp = client.post_order(signed_order, OrderType.FOK)

from py_clob_client.clob_types import OpenOrderParams

# Get open orders
orders = client.get_orders(OpenOrderParams())

# Cancel specific order
client.cancel("ORDER_ID")

# Cancel all orders
client.cancel_all()

import asyncio
from py_clob_client.client import ClobClient

async def scan_for_arbitrage():
    client = ClobClient("https://clob.polymarket.com")

    while True:
        markets = client.get_simplified_markets()

        for market in markets:
            if len(market.get('tokens', [])) == 2:
                yes_token = market['tokens'][0]
                no_token = market['tokens'][1]

                yes_price = float(client.get_midpoint(yes_token['token_id']))
                no_price = float(client.get_midpoint(no_token['token_id']))

                combined = yes_price + no_price

                if combined < 0.98:
                    print(f"ARBITRAGE: {market['question']}")
                    print(f"YES: {yes_price}, NO: {no_price}")
                    print(f"Combined: {combined}")
                    print(f"Profit: {((1/combined) - 1) * 100:.2f}%")

        await asyncio.sleep(30)

asyncio.run(scan_for_arbitrage())