GET /markets/updown

# All active up/down markets
curl -H "X-API-Key: $API_KEY" \
  https://api.polysimulator.com/v1/markets/updown

# Filter by asset and interval
curl -H "X-API-Key: $API_KEY" \
  "https://api.polysimulator.com/v1/markets/updown?asset=BTC&interval=1H"

{
  "markets": [
    {
      "event_id": "evt_abc123",
      "condition_id": "0xabc123...",
      "slug": "btc-updown-1h-1770706800",
      "title": "BTC 1H Up/Down — March 15",
      "description": "Will BTC go up or down in the next hour?",
      "asset": "BTC",
      "interval": "1H",
      "time_range": "1:00 PM-2:00 PM ET",
      "date_display": "March 15",
      "start_date": "2026-03-15T13:00:00+00:00",
      "end_date": "2026-03-15T14:00:00Z",
      "active": true,
      "closed": false,
      "resolved": false,
      "tags": ["up-or-down", "bitcoin", "1h"],
      "markets": [
        {
          "id": "12345",
          "condition_id": "0xabc123...",
          "question": "Will Bitcoin go up or down in the next hour?",
          "outcomes": "[\"Up\", \"Down\"]",
          "outcome_prices": "[\"0.55\", \"0.45\"]",
          "token_ids": "[\"71321045...\", \"82432156...\"]"
        }
      ],
      "live_price": {
        "buy": 0.55,
        "sell": 0.45,
        "updated_at": "2026-03-15T13:44:58Z"
      },
      "group_item_threshold": null,
      "image": "https://polymarket.com/images/btc.png",
      "icon": "https://polymarket.com/icons/btc.svg"
    }
  ],
  "total": 42,
  "interval_counts": { "5M": 0, "15M": 0, "1H": 12, "4H": 8, "daily": 6 },
  "asset_counts": { "BTC": 10, "ETH": 8, "SOL": 6 },
  "available_intervals": ["1H", "4H", "daily"],
  "available_assets": ["BTC", "ETH", "SOL", "XRP"],
  "crypto_prices": {
    "BTC": { "price": 98500.50, "change_24h": 2.3 },
    "ETH": { "price": 3850.25, "change_24h": -1.1 }
  },
  "timestamp": "2026-03-15T13:45:00Z",
  "cache_hit": true
}

import json, os, datetime as dt
import requests

BASE = os.environ.get("POLYSIM_BASE_URL", "https://api.polysimulator.com")
HEADERS = {"X-API-Key": os.environ["POLYSIM_API_KEY"], "Content-Type": "application/json"}

def ts(s):
    return dt.datetime.fromisoformat(s.replace("Z", "+00:00"))

# 1. The BTC 5-minute round that is open right now
rounds = requests.get(f"{BASE}/v1/markets/updown", headers=HEADERS,
                      params={"asset": "BTC", "interval": "5M"}).json()["markets"]
now = dt.datetime.now(dt.timezone.utc)
current = next(r for r in rounds if ts(r["start_date"]) <= now < ts(r["end_date"]))
market = current["markets"][0]
cid = market["condition_id"]
outcomes = json.loads(market["outcomes"])       # ["Up", "Down"]
token_ids = json.loads(market["token_ids"])     # same order as outcomes
print(current["slug"], "ends", current["end_date"])

# 2. The Up book (the same levels Polymarket shows for that token)
book = requests.get(f"{BASE}/v1/markets/{cid}/book", headers=HEADERS,
                    params={"outcome": "Up"}).json()
best_ask = min(float(level["price"]) for level in book["asks"])

# 3. Buy 10 Up with a worst-price cap one tick above the ask.
#    Market orders REQUIRE `price` (Polymarket-faithful slippage cap); without
#    it the API returns 400 "Market orders require a 'price' field".
order = requests.post(f"{BASE}/v1/orders", headers=HEADERS, json={
    "market_id": cid, "side": "BUY", "outcome": "Up", "quantity": "10",
    "order_type": "market", "price": f"{min(0.99, best_ask + 0.01):.2f}",
}).json()
print(order["order_id"], order["status"], order["price"], "fee", order.get("fee"))