Benjamin-Cup

Posted on May 30

How to use API to build a Polymarket Trading Bot in Python

#python #tutorial #api #polymarket

Building a Polymarket trading bot using Python allows you to automate prediction market strategies, analyze real-time probabilities, and execute trades programmatically through Polymarket’s APIs.

This guide explains how to use the Polymarket CLOB API, Gamma API, and the official Python SDK (py-clob-client) to build a working trading bot from scratch.

📌 Polymarket API Overview

Polymarket provides three core APIs:

1. CLOB API (Trading Engine)

Handles order placement and execution
Manages order books and trade matching
Requires authentication

Base URL:

https://clob.polymarket.com

2. Gamma API (Market Data)

Market discovery (events, questions, categories)
Token and condition metadata
No authentication required

Base URL:

https://gamma-api.polymarket.com

3. Data API (Analytics)

Historical trades and positions
Volume, open interest, user activity

Base URL:

https://data-api.polymarket.com

📘 Official Docs:
https://docs.polymarket.com/api-reference/introduction ([Polymarket Documentation][1])

⚙️ Prerequisites

Before building your bot, you need:

Python 3.9+
A Polymarket account
A Polygon wallet (private key required)
USDC on Polygon for trading
Basic understanding of REST APIs

Install the official SDK:

pip install py-clob-client

🔐 Step 1: Initialize the Polymarket Client

from py_clob_client.client import ClobClient

API_URL = "https://clob.polymarket.com"

client = ClobClient(
    host=API_URL,
    key="YOUR_WALLET_PRIVATE_KEY",
    chain_id=137  # Polygon Mainnet
)

📊 Step 2: Fetch Market Data (Gamma API)

Use Gamma API to discover markets:

import requests

url = "https://gamma-api.polymarket.com/markets"

response = requests.get(url)
markets = response.json()

for m in markets[:5]:
    print(m["question"], m["id"])

👉 This gives you active prediction markets you can trade.

📈 Step 3: Get Order Book Data (CLOB API)

market_id = "123456"

orderbook = client.get_order_book(market_id)

print("Best Bid:", orderbook["bids"][0])
print("Best Ask:", orderbook["asks"][0])

💰 Step 4: Place a Trade

Place a BUY order

from py_clob_client.clob_types import OrderArgs
from py_clob_client.order_builder.constants import BUY

order = OrderArgs(
    token_id="TOKEN_ID_HERE",
    side=BUY,
    price=0.52,
    size=10
)

result = client.create_order(order)
print(result)

🧠 Step 5: Example Trading Strategy (Simple Bot Logic)

A basic momentum strategy:

import time

THRESHOLD = 0.55

while True:
    orderbook = client.get_order_book(market_id)

    best_ask = float(orderbook["asks"][0]["price"])

    if best_ask < THRESHOLD:
        print("Buying opportunity detected")

        order = OrderArgs(
            token_id="TOKEN_ID",
            side=BUY,
            price=best_ask,
            size=5
        )

        client.create_order(order)

    time.sleep(10)

⚠️ Important Notes

Polymarket uses EIP-712 signed transactions
Token IDs differ from Gamma “condition IDs”
Rate limits apply (~100 requests / 10 seconds for reads)
Always implement retry logic for production bots

🧪 Production-Ready Improvements

To make your bot production-ready, consider adding:

✔ Error Handling

try:
    client.create_order(order)
except Exception as e:
    print("Order failed:", e)

✔ Retry Logic

Handle HTTP 429 rate limits
Exponential backoff strategy

✔ Logging System

Track orders
Store fills in a database (PostgreSQL / MongoDB)

✔ Strategy Layer

Arbitrage detection
Sentiment analysis (Twitter / news APIs)
Market-making logic

🔗 Official Documentation

Polymarket API Reference:
https://docs.polymarket.com/api-reference/introduction ([Polymarket Documentation][1])
Gamma API (Market Data):
https://gamma-api.polymarket.com
CLOB API (Trading Engine):
https://clob.polymarket.com

❓ FAQ

1. What is a Polymarket trading bot?

A bot that automatically places trades on prediction markets using Polymarket APIs based on predefined strategies.

2. Is Polymarket API free to use?

Yes, market data APIs are free. Trading requires a funded wallet with USDC on Polygon.

3. Do I need crypto to use the bot?

Yes. You need USDC on the Polygon network to execute trades.

4. What is the hardest part of building a bot?

The most common challenge is mapping:

Gamma condition_id → CLOB token_id

This mismatch often confuses beginners.

5. Can I run the bot 24/7?

Yes, but you should deploy it on:

VPS (DigitalOcean, AWS, etc.)
Or Docker container with restart policies

6. Is Polymarket legal to use?

It depends on your jurisdiction. Always check local regulations before trading.

🚀 Conclusion

Building a Polymarket trading bot in Python is straightforward once you understand:

Gamma API → market discovery
CLOB API → trading execution
py-clob-client → SDK abstraction layer

With a proper architecture, you can scale from a simple bot to a fully automated trading system.

🤝 Collaboration & Contact

If you’re interested in building trading bots, buy trading bots, collaborating, exploring strategy improvements, or discussing about this system, feel free to reach out.

I’m especially open to connecting with:

Quant traders
Engineers building trading infrastructure
Researchers in prediction markets
Investors interested in market inefficiencies

📌 GitHub Repository

This repo has some Polymarket several bots in this system.
You can explore the full implementation, strategy logic, and ongoing updates about 5 min crypto market here:

Benjamin-cup / Polymarket-trading-bot-python-V2

Polymarket Trading Bot Polymarket Trading Bot Polymarket Trading Bot Polymarket Trading Bot Polymarket Trading Bot Polymarket Trading Bot Polymarket Trading Bot Polymarket Trading Bot Polymarket Trading Bot Polymarket Trading Bot Polymarket Trading Bot Polymarket Trading Bot Polymarket Trading Bot Polymarket Trading Bot Polymarket Trading Bot

Polymarket Trading Bot | Polymarket Arbitrage Bot

An open-source and Strong Strategy collection of Polymarket trading bot and arbitrage bot in Python for high-performance automated trading on polymarket crypto 5min markets.

Features

Explosive growth of Polymarket with surging trading volume and new short-term markets
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Included Trading Bots

Designed for arbitrage, directional strategies, and ultra-short-term markets (including 5-minute rounds), this bot framework provides a robust foundation for building and scaling automated trading strategies on Polymarket .