Trading Polymarket

Signature Types

ClobClient - Complete API (60+ Methods)

Initialization

from py_clob_client.client import ClobClient
from py_clob_client.clob_types import (
    OrderArgs, MarketOrderArgs, ApiCreds, OrderType,
    BookParams, TradeParams, OpenOrderParams, BalanceAllowanceParams,
    AssetType, OrderScoringParams, OrdersScoringParams, DropNotificationParams
)
from py_clob_client.order_builder.constants import BUY, SELL
from py_clob_client.constants import POLYGON  # 137

# Level 2 Auth (full trading access)
client = ClobClient(
    host="https://clob.polymarket.com",
    key=os.getenv("PRIVATE_KEY"),           # Private key for signing
    chain_id=POLYGON,                        # 137 for mainnet, 80002 for Amoy testnet
    funder=os.getenv("POLY_FUNDER_ADDRESS"), # Wallet address (for proxy wallets)
    signature_type=2                         # 0=EOA, 1=MagicLink, 2=Proxy
)

# Set API credentials for authenticated endpoints
client.set_api_creds(ApiCreds(
    api_key=os.getenv("POLY_API_KEY"),
    api_secret=os.getenv("POLY_API_SECRET"),
    api_passphrase=os.getenv("POLY_API_PASSPHRASE")
))

Health & Configuration

client.get_ok()                    # Check if server is up
client.get_server_time()           # Get server timestamp
client.get_address()               # Your signer's public address
client.get_collateral_address()    # USDC contract address
client.get_conditional_address()   # CTF contract address
client.get_exchange_address()      # Exchange contract (neg_risk=False default)

Market Data - Single Token

# Get prices and spreads
client.get_midpoint(token_id)              # Mid market price
client.get_price(token_id, side="BUY")     # Best price for side
client.get_spread(token_id)                # Current spread
client.get_last_trade_price(token_id)      # Last executed trade price

# Get full orderbook
orderbook = client.get_order_book(token_id)
# Returns: OrderBookSummary with bids, asks, tick_size, neg_risk, timestamp, hash

Market Data - Batch (Multiple Tokens)

params = [
    BookParams(token_id="TOKEN1", side="BUY"),
    BookParams(token_id="TOKEN2", side="SELL")
]

client.get_midpoints(params)           # Multiple midpoints
client.get_prices(params)              # Multiple prices
client.get_spreads(params)             # Multiple spreads
client.get_order_books(params)         # Multiple orderbooks
client.get_last_trades_prices(params)  # Multiple last prices

Market Metadata

client.get_tick_size(token_id)      # Returns: "0.1", "0.01", "0.001", or "0.0001"
client.get_neg_risk(token_id)       # Returns: True/False (negative risk market)
client.get_fee_rate_bps(token_id)   # Returns: fee rate in basis points (0 or 1000)

Order Types

from py_clob_client.clob_types import OrderType

OrderType.GTC   # Good Till Cancelled - stays open until filled/cancelled
OrderType.FOK   # Fill Or Kill - fill entirely immediately or cancel
OrderType.GTD   # Good Till Date - expires at timestamp (min 60 seconds)
OrderType.FAK   # Fill And Kill - fill what's possible, cancel rest

When to Use Each Order Type

OrderArgs - Limit Orders

OrderArgs(
    token_id: str,           # Token ID (outcome to trade)
    price: float,            # Price 0.01-0.99
    size: float,             # Number of shares
    side: str,               # "BUY" or "SELL" (or use BUY/SELL constants)
    fee_rate_bps: int = 0,   # Optional: fee rate in bps (0 or check market)
    nonce: int = 0,          # Optional: unique nonce for cancellation
    expiration: int = 0,     # Optional: expiry timestamp (0 = GTC, use timestamp for GTD)
    taker: str = ZERO_ADDRESS  # Optional: specific taker (ZERO_ADDRESS = anyone)
)

MarketOrderArgs - Market Orders

MarketOrderArgs(
    token_id: str,           # Token ID
    amount: float,           # Total USDC amount to spend (BUY) or shares (SELL)
    side: str,               # "BUY" or "SELL"
    price: float = 0,        # Optional: worst acceptable price (slippage protection)
    fee_rate_bps: int = 0,   # Optional: fee rate
    nonce: int = 0,          # Optional: nonce
    taker: str = ZERO_ADDRESS,  # Optional: taker address
    order_type: OrderType = FOK  # Optional: FOK (default) or FAK
)

Complete Order Examples

from py_clob_client.order_builder.constants import BUY, SELL

# 1. LIMIT BUY (GTC) - sits on book until filled
order = client.create_and_post_order(
    OrderArgs(token_id=TOKEN_ID, price=0.45, size=100.0, side=BUY)
)

# 2. LIMIT SELL (GTC)
order = client.create_and_post_order(
    OrderArgs(token_id=TOKEN_ID, price=0.55, size=50.0, side=SELL)
)

# 3. MARKET BUY - spend $100 USDC at current prices (FOK)
signed = client.create_market_order(
    MarketOrderArgs(token_id=TOKEN_ID, amount=100.0, side=BUY)
)
result = client.post_order(signed, orderType=OrderType.FOK)

# 4. MARKET SELL - sell all shares immediately (FOK)
signed = client.create_market_order(
    MarketOrderArgs(token_id=TOKEN_ID, amount=my_shares, side=SELL)
)
result = client.post_order(signed, orderType=OrderType.FOK)

# 5. POST-ONLY MAKER ORDER (avoid taker fees, earn rebates)
signed = client.create_order(
    OrderArgs(token_id=TOKEN_ID, price=0.44, size=100.0, side=BUY)
)
result = client.post_order(signed, orderType=OrderType.GTC, post_only=True)
# If order would cross spread, it gets REJECTED instead of taking

# 6. GOOD TIL DATE (GTD) - expires after timestamp
import time
expiry = int(time.time()) + 300  # 5 minutes from now
signed = client.create_order(
    OrderArgs(token_id=TOKEN_ID, price=0.50, size=100.0, side=BUY, expiration=expiry)
)
result = client.post_order(signed, orderType=OrderType.GTD)

# 7. FILL AND KILL (FAK) - fill what you can, cancel rest
signed = client.create_market_order(
    MarketOrderArgs(token_id=TOKEN_ID, amount=1000.0, side=BUY)
)
result = client.post_order(signed, orderType=OrderType.FAK)

Order Operations

Create and Post Orders

# SIMPLE: Create and post in one call (recommended)
result = client.create_and_post_order(
    OrderArgs(
        token_id="123456789012345678901234567890",
        price=0.45,
        size=10.0,
        side="BUY"
    )
)
# Returns: {"orderID": "...", "status": "...", ...}

# ADVANCED: Separate create and post
order = client.create_order(OrderArgs(...))  # Returns SignedOrder
result = client.post_order(order, orderType=OrderType.GTC, post_only=False)

# Market order (calculates price automatically)
result = client.create_market_order(
    MarketOrderArgs(
        token_id="...",
        amount=100.0,    # Spend $100 USDC
        side="BUY"
    )
)

# Calculate expected fill price before market order
price = client.calculate_market_price(
    token_id="...",
    side="BUY",
    amount=100.0,
    order_type=OrderType.FOK
)

Cancel Orders

client.cancel(order_id="ORDER_ID")           # Cancel specific order
client.cancel_orders(["ID1", "ID2", "ID3"])  # Cancel multiple
client.cancel_all()                          # Cancel ALL open orders
client.cancel_market_orders(                 # Cancel by market/asset
    market="CONDITION_ID",
    asset_id="TOKEN_ID"
)

Query Orders

# Get all open orders
orders = client.get_orders(
    params=OpenOrderParams(
        id="ORDER_ID",      # Optional: specific order
        market="COND_ID",   # Optional: filter by market
        asset_id="TOKEN"    # Optional: filter by token
    ),
    next_cursor="MA=="      # For pagination
)

# Get specific order
order = client.get_order(order_id="ORDER_ID")

Trade History

trades = client.get_trades(
    params=TradeParams(
        id="TRADE_ID",           # Optional: specific trade
        maker_address="0x...",   # Optional: filter by maker
        market="CONDITION_ID",   # Optional: filter by market
        asset_id="TOKEN_ID",     # Optional: filter by token
        before="2024-01-01",     # Optional: before date
        after="2023-01-01"       # Optional: after date
    ),
    next_cursor="MA=="
)

Balance & Allowance

# Check balance and allowances
balance = client.get_balance_allowance(
    params=BalanceAllowanceParams(
        asset_type=AssetType.COLLATERAL,  # USDC balance
        # or AssetType.CONDITIONAL         # Token balance
        token_id="TOKEN_ID"                # For conditional tokens
    )
)

# Update/refresh allowance cache
client.update_balance_allowance(params=...)

Market Discovery

Get Markets from CLOB

# All active markets
markets = client.get_markets(next_cursor="MA==")
simplified = client.get_simplified_markets()

# Specific market
market = client.get_market(condition_id="CONDITION_ID")

# Market trade events
events = client.get_market_trades_events(condition_id="CONDITION_ID")

# Sampling/featured markets
client.get_sampling_markets()
client.get_sampling_simplified_markets()

Get Markets from Gamma API (More Details)

import requests

def search_markets(query: str, limit: int = 10):
    """Search Polymarket markets by keyword"""
    url = "https://gamma-api.polymarket.com/markets"
    params = {
        "_q": query,
        "active": "true",
        "closed": "false",
        "_limit": limit
    }
    r = requests.get(url, params=params)
    return r.json()

# Get market details
markets = search_markets("bitcoin")
for m in markets:
    print(f"Question: {m['question']}")
    print(f"Condition ID: {m['condition_id']}")
    print(f"Volume: ${m.get('volume', 0):,.2f}")
    for token in m.get('tokens', []):
        print(f"  {token['outcome']}: {token['token_id']}")
        print(f"    Price: {float(token['price']):.2f}")

On-Chain Operations

Check Token Balance (Position Size)

import requests

CTF_CONTRACT = "0x4D97DCd97eC945f40cF65F87097ACe5EA0476045"
RPC_URL = "https://polygon-rpc.com/"

def get_token_balance(wallet: str, token_id: str) -> float:
    """Get balance of a specific outcome token in shares"""
    token_int = int(token_id)
    # ERC-1155 balanceOf(address,uint256)
    data = f"0x00fdd58e000000000000000000000000{wallet[2:].lower()}{token_int:064x}"

    r = requests.post(RPC_URL, json={
        "jsonrpc": "2.0",
        "method": "eth_call",
        "params": [{"to": CTF_CONTRACT, "data": data}, "latest"],
        "id": 1
    })

    result = r.json().get("result", "0x0")
    balance = int(result, 16) / 1e6  # Convert from raw to shares
    return balance

# Usage
balance = get_token_balance(
    wallet="0x7c2211103e7Fbb257Ac6fa59f972cfd8bc9D4795",
    token_id="12345678901234567890"
)
print(f"Position: {balance} shares")

Check USDC Balance

USDC_CONTRACT = "0x2791Bca1f2de4661ED88A30C99A7a9449Aa84174"

def get_usdc_balance(wallet: str) -> float:
    """Get USDC balance on Polygon"""
    # ERC-20 balanceOf(address)
    data = f"0x70a08231000000000000000000000000{wallet[2:].lower()}"

    r = requests.post(RPC_URL, json={
        "jsonrpc": "2.0",
        "method": "eth_call",
        "params": [{"to": USDC_CONTRACT, "data": data}, "latest"],
        "id": 1
    })

    result = r.json().get("result", "0x0")
    return int(result, 16) / 1e6  # USDC has 6 decimals

API Key Management

# Create new API key
creds = client.create_api_key(nonce=0)

# Derive existing API key (if you lost creds but have private key)
creds = client.derive_api_key(nonce=0)

# Create or derive (tries both)
creds = client.create_or_derive_api_creds(nonce=0)

# Get all your API keys
keys = client.get_api_keys()

# Delete current API key
client.delete_api_key()

# Readonly API keys (for monitoring only)
readonly = client.create_readonly_api_key()
client.get_readonly_api_keys()
client.delete_readonly_api_key(key="...")
client.validate_readonly_api_key(address="0x...", key="...")

Advanced Features

Order Heartbeat (Keep Orders Alive)

# Start heartbeat - if not sent within 10s, all orders cancelled
heartbeat_id = client.post_heartbeat(heartbeat_id=None)

# Continue sending heartbeats
while trading:
    client.post_heartbeat(heartbeat_id=heartbeat_id)
    time.sleep(5)

Order Scoring

# Check if order is scoring (earning rewards)
is_scoring = client.is_order_scoring(
    params=OrderScoringParams(order_id="...")
)

# Check multiple orders
scores = client.are_orders_scoring(
    params=OrdersScoringParams(order_ids=["ID1", "ID2"])
)

Notifications

notifications = client.get_notifications()
client.drop_notifications(params=DropNotificationParams(...))

Fee Structure

IMPORTANT: Most Polymarket markets have ZERO fees (0% maker, 0% taker).

15-min Crypto Markets (Exception)

Only 15-minute BTC/ETH/SOL/XRP price prediction markets have fees:

fee = shares × 0.25 × (price × (1 - price))²

TAKER = crosses spread = PAYS fee MAKER = adds liquidity = NO fee + earns rebates

To be a maker: Post orders that don't immediately fill (inside the spread).

Decimal Precision Rules

Min order size: $1 per side

Complete Trading Example

#!/usr/bin/env python3
"""
Production-ready Polymarket trading script
"""

import os
import time
import requests
from py_clob_client.client import ClobClient
from py_clob_client.clob_types import OrderArgs, ApiCreds, OrderType

# Initialize
client = ClobClient(
    "https://clob.polymarket.com",
    key=os.getenv("PRIVATE_KEY"),
    chain_id=137,
    funder=os.getenv("POLY_FUNDER_ADDRESS"),
    signature_type=2
)
client.set_api_creds(ApiCreds(
    api_key=os.getenv("POLY_API_KEY"),
    api_secret=os.getenv("POLY_API_SECRET"),
    api_passphrase=os.getenv("POLY_API_PASSPHRASE")
))

TOKEN_ID = "YOUR_TOKEN_ID"
WALLET = os.getenv("POLY_FUNDER_ADDRESS")
CTF = "0x4D97DCd97eC945f40cF65F87097ACe5EA0476045"

def get_balance(token_id):
    """Get position size"""
    token_int = int(token_id)
    data = f"0x00fdd58e000000000000000000000000{WALLET[2:].lower()}{token_int:064x}"
    r = requests.post("https://polygon-rpc.com/", json={
        "jsonrpc": "2.0", "method": "eth_call",
        "params": [{"to": CTF, "data": data}, "latest"], "id": 1
    })
    return int(r.json().get("result", "0x0"), 16) / 1e6

def get_orderbook(token_id):
    """Get current bid/ask"""
    book = client.get_order_book(token_id)
    return {
        "best_bid": float(book.bids[0].price) if book.bids else 0,
        "best_ask": float(book.asks[0].price) if book.asks else 1
    }

# Check position
position = get_balance(TOKEN_ID)
print(f"Current position: {position} shares")

# Get market
book = get_orderbook(TOKEN_ID)
print(f"Bid: {book['best_bid']:.2f}, Ask: {book['best_ask']:.2f}")

# Place a buy order (maker - inside spread)
buy_price = book['best_bid'] + 0.01  # 1 cent above bid
if buy_price < book['best_ask']:  # Ensure we're maker
    result = client.create_and_post_order(OrderArgs(
        token_id=TOKEN_ID,
        price=buy_price,
        size=10.0,
        side="BUY"
    ))
    print(f"Buy order placed: {result}")

# Place a sell order (market sell via FOK)
if position > 0:
    result = client.create_and_post_order(OrderArgs(
        token_id=TOKEN_ID,
        price=0.01,  # Lowest price = immediate fill
        size=position,
        side="SELL"
    ))
    print(f"Sold position: {result}")

Error Handling

from py_clob_client.exceptions import PolyApiException