Polymarket API Guide

import httpx

# Fetch the top Polymarket markets by 24-hour volume
resp = httpx.get("https://gamma-api.polymarket.com/markets", params={
    "limit": 10,
    "active": True,
    "order": "volume24hr",
    "ascending": False,
})

for market in resp.json():
    yes_price = market["outcomePrices"][0] if market.get("outcomePrices") else "N/A"
    print(f"{market['question']} | YES: {yes_price} | Vol: ${float(market.get('volume24hr', 0)):,.0f}")

pip install py-clob-client

from py_clob_client.client import ClobClient

client = ClobClient(
    host="https://clob.polymarket.com",
    key="YOUR_API_KEY",
    chain_id=137,  # Polygon mainnet
)

# List available markets
markets = client.get_markets()

# Get order book for a specific token
book = client.get_order_book(token_id="YOUR_TOKEN_ID")
print(f"Best bid: {book.bids[0].price if book.bids else 'none'}")
print(f"Best ask: {book.asks[0].price if book.asks else 'none'}")

# Place a limit buy order
order = client.create_and_post_order(
    token_id="YOUR_TOKEN_ID",
    price=0.65,      # Price per share in USDC
    size=100,         # Number of shares
    side="BUY",
)
print(f"Order ID: {order['orderID']}")

# Cancel an order
client.cancel(order_id="YOUR_ORDER_ID")

# Get open orders
open_orders = client.get_orders()

# Get positions
positions = client.get_positions()

import httpx

slug = "will-bitcoin-hit-100k-2026"
resp = httpx.get(f"https://gamma-api.polymarket.com/markets/{slug}")
market = resp.json()
print(f"{market['question']} — condition: {market['conditionId']}")

{
  "bids": [
    { "price": "0.65", "size": "500" },
    { "price": "0.64", "size": "1200" }
  ],
  "asks": [
    { "price": "0.66", "size": "300" },
    { "price": "0.67", "size": "800" }
  ]
}

headers = sign_request("GET", "/positions")
resp = httpx.get("https://clob.polymarket.com/positions", headers=headers)
positions = resp.json()

for pos in positions:
    print(f"Token: {pos['asset']['token_id']} | Size: {pos['size']} | Avg: ${pos['avg_price']}")

{
  "question": "Will the Fed cut rates in Q2 2026?",
  "conditionId": "0xabc123...def456",
  "slug": "will-the-fed-cut-rates-q2-2026",
  "outcomes": ["Yes", "No"],
  "outcomePrices": ["0.62", "0.38"],
  "volume": "2450000",
  "volume24hr": 185000,
  "liquidity": "340000",
  "endDate": "2026-06-30T23:59:59Z",
  "active": true,
  "clobTokenIds": ["0x111...aaa", "0x222...bbb"]
}

Market (condition ID: 0xabc...123)
  |
  +-- Yes outcome (token ID: 0x111...aaa)
  |
  +-- No outcome (token ID: 0x222...bbb)

import httpx

# 1. Discover a market
resp = httpx.get("https://gamma-api.polymarket.com/markets", params={
    "limit": 1, "active": True, "order": "volume24hr", "ascending": False,
})
market = resp.json()[0]
condition_id = market["conditionId"]
yes_token_id = market["clobTokenIds"][0]  # Index 0 = Yes outcome
no_token_id = market["clobTokenIds"][1]   # Index 1 = No outcome

print(f"Market: {market['question']}")
print(f"Condition ID: {condition_id}")
print(f"Yes token: {yes_token_id}")
print(f"No token: {no_token_id}")

# 2. Get order book for the Yes outcome
headers = sign_request("GET", "/book")
book = httpx.get("https://clob.polymarket.com/book", headers=headers, params={
    "token_id": yes_token_id,
}).json()