trading-manifold

Manifold Markets Trading Skill

Real, working methods to bet on Manifold Markets using Mana (play money that can be donated to charity).

Setup

Get your API key from: https://manifold.markets/profile (API key section)

import os
import requests

API_URL = "https://api.manifold.markets/v0"
API_KEY = os.getenv("MANIFOLD_API_KEY")

def headers():
    return {
        "Authorization": f"Key {API_KEY}",
        "Content-Type": "application/json"
    }

Search Markets

def search_markets(query: str, limit: int = 10):
    """Search for markets"""
    r = requests.get(f"{API_URL}/search-markets", params={
        "term": query,
        "limit": limit,
        "filter": "open",
        "sort": "liquidity"
    })
    r.raise_for_status()
    markets = r.json()

    for m in markets[:5]:
        prob = m.get("probability", 0.5)
        print(f"\nMarket: {m['question']}")
        print(f"ID: {m['id']}")
        print(f"Probability: {prob*100:.1f}%")
        print(f"URL: {m.get('url', '')}")

    return markets

markets = search_markets("AI")

Get Market by ID or Slug

def get_market(id_or_slug: str):
    """Get market details"""
    # Try by ID first
    r = requests.get(f"{API_URL}/market/{id_or_slug}")
    if r.status_code == 404:
        # Try by slug
        r = requests.get(f"{API_URL}/slug/{id_or_slug}")

    r.raise_for_status()
    return r.json()

market = get_market("will-gpt5-be-released-before-2025")
print(f"Question: {market['question']}")
print(f"Probability: {market.get('probability', 0.5)*100:.1f}%")

Place a Bet

def place_bet(
    market_id: str,
    amount: int,           # Mana amount to bet
    outcome: str = "YES",  # "YES" or "NO"
    limit_prob: float = None  # Optional limit order probability
):
    """
    Place a bet on Manifold

    Args:
        market_id: The market ID (not slug!)
        amount: Amount of Mana to bet
        outcome: "YES" or "NO"
        limit_prob: Optional - if set, creates a limit order at this probability
    """
    payload = {
        "contractId": market_id,
        "amount": amount,
        "outcome": outcome
    }

    if limit_prob is not None:
        payload["limitProb"] = limit_prob

    r = requests.post(f"{API_URL}/bet", headers=headers(), json=payload)
    r.raise_for_status()
    result = r.json()

    print(f"Bet placed!")
    print(f"Shares: {result.get('shares', 0):.2f}")
    print(f"Probability after: {result.get('probAfter', 0)*100:.1f}%")

    return result

# Market bet - buys at current price
result = place_bet(
    market_id="abc123",
    amount=100,  # 100 Mana
    outcome="YES"
)

# Limit order - only fills at 40% or below
result = place_bet(
    market_id="abc123",
    amount=100,
    outcome="YES",
    limit_prob=0.40
)