Manifold Markets API

Quick Reference

https://api.manifold.markets/v0

https://api.manifold.markets

Authorization: Key {api_key}

Authentication

Get your API key at: https://manifold.markets/profile

For scripts (Python)

import os
import requests

API_KEY = os.getenv("MANIFOLD_API_KEY")
BASE = "https://api.manifold.markets/v0"
headers = {"Authorization": f"Key {API_KEY}"}

r = requests.get(f"{BASE}/me", headers=headers)

For shell commands (curl)

If an authenticated request is needed, ask the user to export their API key first:

export MANIFOLD_API_KEY="your-key-here"

The user can get their key from https://manifold.markets/profile or their

.env

Then use in curl commands:

curl -H "Authorization: Key $MANIFOLD_API_KEY" https://api.manifold.markets/v0/me

The export lasts for the terminal session (until the window is closed).

Which endpoints need auth?

• No auth needed: Reading public markets, users, bets, comments
• Auth required: Placing bets, posting comments, creating markets, accessing own portfolio/notifications

Common Operations

Get a Market

r = requests.get(f"{BASE}/market/{market_id}")
r = requests.get(f"{BASE}/slug/{market_slug}")

Search Markets

r = requests.get(f"{BASE}/search-markets", params={
    "term": "AI",
    "filter": "open",      # all, open, closed, resolved, closing-this-month, closing-next-month
    "sort": "liquidity",   # See sort options below
    "limit": 50,           # Max 100
})

# Valid sort options (from schema.ts):
# score (default), newest, daily-score, freshness-score, 24-hour-vol,
# most-popular, liquidity, subsidy, last-updated, close-date,
# start-time, resolve-date, random, bounty-amount, prob-descending, prob-ascending
#
# NOTE: There is NO "volume" sort. Use Supabase for all-time volume ranking.

Place a Bet

# Market order
r = requests.post(f"{BASE}/bet", headers=headers, json={
    "contractId": market_id,
    "amount": 100,
    "outcome": "YES",
})

# Limit order (IOC - expires quickly)
r = requests.post(f"{BASE}/bet", headers=headers, json={
    "contractId": market_id,
    "amount": 100,
    "outcome": "YES",
    "limitProb": 0.60,
    "expiresMillisAfter": 10,
})

# Multiple choice (requires answerId)
r = requests.post(f"{BASE}/bet", headers=headers, json={
    "contractId": market_id,
    "answerId": answer_id,
    "amount": 100,
    "outcome": "YES",
})

Sell Shares

r = requests.post(f"{BASE}/market/{market_id}/sell", headers=headers, json={
    "outcome": "YES",
    "shares": 50,          # Optional, sells all if omitted
    "answerId": answer_id, # Required for MC
})

Get User & Positions

r = requests.get(f"{BASE}/user/{username}")
r = requests.get(f"{BASE}/market/{market_id}/positions", params={"userId": user_id})

Market Types

BINARY

cpmm-1

p

MULTIPLE_CHOICE

cpmm-multi-1

p=0.5

PSEUDO_NUMERIC

cpmm-1

POLL

none

BOUNTIED_QUESTION

none

Linked vs Unlinked Multi-Choice

shouldAnswersSumToOne

• false

  → Independent answers (each is its own YES/NO)

• true

  → Mutually exclusive (probabilities sum to 1)

Market State

A market can be bet on only if:

trading_allowed = (
    not market.get("isResolved") and
    (not market.get("closeTime") or market["closeTime"] > time.time() * 1000) and
    market.get("mechanism") != "none" and
    (answer is None or not answer.get("resolution"))  # For MC
)

AMM Probability Formula

# General formula
prob = pool_no**(1-p) / (pool_yes**p + pool_no**(1-p))

# Multi-choice (always p=0.5)
prob = pool_no / (pool_yes + pool_no)

Common Gotchas

close_time_sec = market["closeTime"] / 1000

params={"perAnswer": "true"}

descriptionHtml

answerId

answers

description

answer["pool"]["YES"]

answer["pool"]["NO"]

/v0/

sort=volume

profitByTopic

for item in profitByTopic

winRate

maxDrawdown

datetime.now(timezone.utc).isoformat()

Common Recipes

Top Markets by All-Time Volume

The REST API cannot sort by all-time volume. Use Supabase instead:

from supabase import create_client

SUPABASE_URL = "https://pxidrgkatumlvfqaxcll.supabase.co"
SUPABASE_ANON_KEY = "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJzdXBhYmFzZSIsInJlZiI6InB4aWRyZ2thdHVtbHZmcWF4Y2xsIiwicm9sZSI6ImFub24iLCJpYXQiOjE2Njg5OTUzOTgsImV4cCI6MTk4NDU3MTM5OH0.d_yYtASLzAoIIGdXUBIgRAGLBnNow7JG2SoaNMQ8ySg"

sb = create_client(SUPABASE_URL, SUPABASE_ANON_KEY)

# Top 10 by all-time volume (volume is in data->volume JSON path)
result = (
    sb.table("contracts")
    .select("id, question, slug, visibility, data")
    .eq("visibility", "public")
    .order("data->volume", desc=True)
    .limit(10)
    .execute()
)

for m in result.data:
    vol = m["data"].get("volume", 0)
    creator = m["data"].get("creatorUsername", "")
    print(f"{int(vol):,} M - {m['question']}")
    print(f"  https://manifold.markets/{creator}/{m['slug']}")

Top Markets by 24-Hour Volume

Use the REST API with

sort=24-hour-vol

r = requests.get(f"{BASE}/search-markets", params={
    "sort": "24-hour-vol",
    "filter": "open",
    "limit": 10,
})

Error Responses

{"message": "Contract not found"}
{"message": "Insufficient balance"}
{"message": "Market is closed"}

Errors return HTTP 4xx/5xx with a

message

Reference Files

Organized by domain:

Parallel Fetching

from concurrent.futures import ThreadPoolExecutor

def fetch_markets_parallel(market_ids, max_workers=10):
    def fetch_one(mid):
        return requests.get(f"{BASE}/market/{mid}").json()

    with ThreadPoolExecutor(max_workers=max_workers) as ex:
        return list(ex.map(fetch_one, market_ids))

# Batch probability fetch (100x faster, up to 100 markets)
r = requests.get(f"{BASE}/market-probs",
    params=[("ids[]", mid) for mid in market_ids[:100]])

# Batch market fetch (root path) - note bracket notation
r = requests.get("https://api.manifold.markets/markets-by-ids",
    params=[("ids[]", mid) for mid in market_ids])

Caching Bulk Data

For long-running operations (scanning users, bulk fetches, etc.), cache to

~/.cache/manifold-markets-skill/

processed_ids

Admin / Internal Endpoints

The following endpoints exist but require special privileges or are for internal use:

• Admin:

  admin-*

  ,

  super-ban-user

  ,

  recover-user

  ,

  anonymize-user

  ,

  toggle-system-trading-status

• Moderation:

  get-mod-reports

  ,

  update-mod-report

  ,

  dismiss-user-report

• Identity verification (GIDX):

  *-gidx

  endpoints for KYC/sweepstakes compliance
• Analytics tracking:

  record-contract-view

  ,

  record-comment-view

  ,

  record-contract-interaction

Don't use these unless you have appropriate permissions.

Official Resources

• API Docs: https://docs.manifold.markets/api
• API Schema: https://github.com/manifoldmarkets/manifold/blob/main/common/src/api/schema.ts
• Market Types: https://github.com/manifoldmarkets/manifold/blob/main/common/src/contract.ts