API preview

No authentication and no published rate limit. CORS is open to every origin, so you can call it straight from a browser while the API product is in preview. Please cache aggressively — the upstream feeds (Open-Meteo, Kalshi, Polymarket) are shared public infrastructure.

Authentication

There is none for the free preview. Send the request. An Authorization header is accepted and ignored, so client libraries written against a keyed build keep working.

curl "https://<your-host>/v1/markets?min_edge_c=10&venue=kalshi"

All tracked markets with live obs, the selected forecast, market-implied temperature and the best-trade edge. This is the scanner as JSON — the site polls this exact route.

{
  "as_of": "2026-07-29T20:12:04Z",
  "count": 14,
  "venues": [
    { "venue": "kalshi", "ok": true, "count": 9 },
    { "venue": "polymarket", "ok": true, "count": 2 }
  ],
  "markets": [
    {
      "ticker": "KXHIGHNY-26JUL29",
      "venue": "kalshi",
      "station": "KNYC",
      "type": "daily_high",
      "closes_at": "2026-07-30T04:00:00Z",
      "obs": { "temp_f": 91.3, "at": "2026-07-29T19:51:00Z", "trend_f_hr": 0.6,
               "source": "open-meteo" },
      "forecast": {
        "high_f": 92.1, "sigma_f": 0.7, "updated_at": "2026-07-29T19:58:00Z",
        "peak_local": "4:40 PM",
        "components": { "model_consensus_f": 91.0,
                        "obs_bias_f": 0.62, "balloon_nudge_f": 0.48 }
      },
      "consensus": { "open_meteo": 90.0, "ecmwf": 91.2, "gfs": 90.5, "icon": 90.1 },
      "selected_forecast": { "source": "open_meteo", "label": "Open-Meteo",
                             "high_f": 90.0, "sigma_f": 1.4 },
      "market_implied_f": 90.8,
      "gap_f": -0.8,
      "edge": { "bucket": "91–92°", "side": "yes", "price_c": 38, "fair_c": 52,
                "edge_c": 14, "ev_pct": 37, "kelly_quarter_pct": 4.8 },
      "volume_usd": 1240000,
      "open_interest_usd": 3100000,
      "spread_c": 1,
      "liquidity_grade": "A",
      "sonde_obs_age_s": 840,
      "simulated": { "balloon_network": true, "market_book": false }
    }
  ]
}

Everything in /v1/markets plus the full bucket ladder. Pass forecast_source to switch the selected probability, fair price and edge lens. Sonde probability remains included for comparison.

{
  "as_of": "2026-07-29T20:12:04Z",
  "market": {
    "ticker": "KXHIGHNY-26JUL29",
    "selected_forecast": { "source": "open_meteo", "label": "Open-Meteo", "high_f": 91.8 },
    "ladder": [
      { "bucket": "≤88°",   "low_f": null, "high_f": 88,
        "price_c": 6, "selected_prob": 0.0242, "selected_fair_c": 2,
        "selected_edge_c": -4, "sonde_prob": 0.0184 },
      { "bucket": "91–92°", "low_f": 91,   "high_f": 92,
        "price_c": 38, "selected_prob": 0.4475, "selected_fair_c": 45,
        "selected_edge_c": 7, "sonde_prob": 0.5216 }
    ],
    "hourly": { "sonde": { "14": 90.6, "15": 91.5, "16": 92.1 },
                "observed": { "14": 90.7, "15": 91.3 },
                "open_meteo": { "14": 89.2, "15": 90.0 } },
    "sounding": { "unit": "SONDE-7", "simulated": true }
  }
}

Latest Open-Meteo current weather plus one value per elapsed local hour. Real public weather data — not Sonde proprietary telemetry.

{
  "station": { "icao": "KNYC", "name": "Central Park",
               "lat": 40.779, "lon": -73.969, "timezone": "America/New_York" },
  "observation": {
    "at": "2026-07-29T19:51:00Z",
    "tempF": 91.3, "dewpointF": 68.0, "humidityPct": 47,
    "windMph": 9.3, "windDir": "SW", "sky": "Mostly Clear",
    "pressureInHg": 29.92, "pressureTrend": "falling",
    "trendFPerHour": 0.6,
    "todayHighF": 91.3, "todayLowF": 76.2,
    "hourlyF": { "8": 81.0, "9": 82.8, "15": 91.3 },
    "source": "open-meteo"
  },
  "simulated": false
}

The Sonde forecast for both market types, with its components broken out — model consensus, observation bias correction, and the simulated balloon contribution — alongside every public model's hourly curve.

{
  "station": { "icao": "KNYC", "timezone": "America/New_York" },
  "date": "2026-07-29",
  "sonde": {
    "daily_high": {
      "value_f": 92.1, "sigma_f": 0.7,
      "peak_local": "4:40 PM", "peak_window_local": "3:47 PM–5:33 PM",
      "components": { "model_consensus_f": 91.0,
                      "obs_bias_f": 0.62, "balloon_nudge_f": 0.48 }
    },
    "overnight_low": { "value_f": 74.8, "sigma_f": 0.9 }
  },
  "models": {
    "ecmwf": { "high_f": 91.2, "run": "12Z run", "run_age_h": 8 },
    "gfs":   { "high_f": 90.5, "run": "18Z run", "run_age_h": 4 }
  },
  "sources": { "models": "open-meteo.com (ECMWF IFS / GFS / ICON)",
               "current_weather": "open-meteo.com",
               "open_meteo_best": "open-meteo.com best_match",
               "balloon_network": "SIMULATED" }
}

The balloon profile nearest a station, or the whole fleet with no near. Simulated — this deployment operates no fleet. Values are generated deterministically and anchored to the live observation, and every response says so.

{
  "notice": "SIMULATED. This deployment operates no balloon fleet…",
  "sounding": {
    "unit": "SONDE-7",
    "station": "KNYC",
    "launched_at": "2026-07-29T17:42:00Z",
    "next_launch_at": "2026-07-29T21:00:00Z",
    "distance_mi": 3.1,
    "bearing": "NE",
    "profile_age_min": 14,
    "surface": { "temp_f": 92.0, "dewpoint_f": 67, "humidity_pct": 44,
                 "wind_mph": 11, "feed": "2-s telemetry" },
    "delta_vs_station_f": 0.7,
    "levels_summary": {
      "t_925mb_c": 26.1,
      "mixed_layer_depth_km": 1.9,
      "lapse_0_1km_c_km": 9.6,
      "low_level_rh_pct": 38
    },
    "delta_vs_open_meteo": { "t_925mb_c": 1.9, "mixed_layer_depth_km": 0.6 },
    "fresher_than_open_meteo_h": 5.7,
    "simulated": true
  }
}

MAE by source, calibration, Brier scores and the cumulative backtest. Resolved values are real. Issued forecasts are archived from the moment this deployment starts; archived days are scored for real, and only days predating the archive are reconstructed.

{
  "notice": "Resolved values are real … Historical forecasts are SIMULATED …",
  "days": 90,
  "simulated_forecasts": true,
  "forecast_source_coverage": { "archived_days": 14, "simulated_days": 76 },
  "mae_by_source": [
    { "name": "Sonde", "maeF": 1.07, "isSonde": true },
    { "name": "ECMWF", "maeF": 1.63 }
  ],
  "calibration": [ { "sayPct": 50, "happensPct": 51.7, "samples": 240 } ],
  "brier": { "sonde": 0.118, "market": 0.154 },
  "pnl": { "final_usd": 12480, "bankroll_usd": 10000 }
}

Settled station-days: what resolved, what each source called, and how the strategy would have settled.

{
  "count": 12,
  "resolutions": [
    { "date": "2026-07-28", "market": "New York · daily high", "icao": "KNYC",
      "sondeF": 91.4, "impliedF": 90.2, "resolvedF": 91,
      "errSonde": 0.4, "errMarket": 0.8, "result": "WIN", "pnlUsd": 212 }
  ]
}

Push channel for obs ticks and edge changes ≥2¢. The original spec called for a WebSocket; this deployment targets serverless hosting where a route handler can’t hold a socket, so it ships as Server-Sent Events — same one-way semantics, works through any proxy, and consumable with a one-line EventSource. Connections are capped at five minutes; reconnect when the stream ends.

const es = new EventSource(
  "https://<your-host>/v1/stream?channels=edges,obs:KNYC&min_edge_c=8"
);

es.addEventListener("edges", (e) => {
  const { markets } = JSON.parse(e.data);   // only markets whose edge moved ≥2¢
  console.log(markets[0].edge);
});

es.addEventListener("obs", (e) => console.log(JSON.parse(e.data)));

Errors

Failures are explicit. A dead upstream returns 502 naming the feed rather than an empty success — if a panel is missing, the API will say why, and /v1/diagnostics reports every feed at once.

{ "error": "observation feed unavailable for KNYC: api.open-meteo.com returned 503" }