Build a prediction market odds bot for X
Kalshi and Polymarket, posted when they move

import os, json, requests
from pathlib import Path

KALSHI = "https://external-api.kalshi.com/trade-api/v2"
OT = {"Authorization": f"Bearer {os.environ['OPENTWEET_API_KEY']}"}
CATEGORY = "Economics"     # or Elections, Politics, Sports, Financials...
MOVE = 0.10                # post when a market moves 10 points or more
MIN_VOLUME = 5_000         # contracts traded in 24h; skips thin markets
LAST = Path("last_prices.json")

last = json.loads(LAST.read_text()) if LAST.exists() else {}
events, cursor = [], None
while True:
    r = requests.get(f"{KALSHI}/events", timeout=30, params={
        "status": "open", "with_nested_markets": "true", "limit": 200, **({"cursor": cursor} if cursor else {})})
    r.raise_for_status()
    page = r.json()
    events += [e for e in page["events"] if e.get("category") == CATEGORY]
    cursor = page.get("cursor")
    if not cursor or len(events) > 300:
        break

now = {}
for ev in events:
    for m in ev["markets"]:
        price = float(m["last_price_dollars"])
        now[m["ticker"]] = price
        before = last.get(m["ticker"])
        if before is None or float(m["volume_24h_fp"]) < MIN_VOLUME:
            continue
        if abs(price - before) >= MOVE:
            arrow = "up" if price > before else "down"
            text = (f"{m['title']}\n\n"
                    f"Kalshi: {price:.0%} yes, {arrow} from {before:.0%} since the last check. "
                    f"{float(m['volume_24h_fp']):,.0f} contracts traded in 24h.")
            requests.post("https://opentweet.io/api/v1/posts", headers=OT,
                          json={"text": text, "publish_now": True}).raise_for_status()

LAST.write_text(json.dumps({**last, **now}))

Will there be a recession in 2027?

Kalshi: 26% yes, down from 46% since the last check. 45,431 contracts traded in 24h.