The physical market, drawn on your CL and NG charts

1. A spot-plus-basis indicator in one file

Paste this into a new NinjaScript indicator (New > NinjaScript Editor > Indicator), compile, and add it to a CL or MCL chart. Add Newtonsoft.Json.dll under References once (right-click in the editor - the DLL ships with NinjaTrader). On intraday charts (bars of 30 minutes or less) it fetches the WTI spot assessment every 30 minutes and prints spot and the chart-minus-spot basis in the corner of the chart.

// NinjaScript indicator: WTI physical spot + basis vs your CL chart.
// NinjaScript is unsandboxed C#, so standard .NET HTTP works. Polling
// every 30 minutes is 48 requests/day - inside the free tier's 50/day.
// ONE-TIME SETUP: NinjaScript Editor > right-click > References > add
// Newtonsoft.Json.dll (it ships in NinjaTrader's bin folder).
using System;
using System.Net.Http;
using Newtonsoft.Json.Linq;
using NinjaTrader.NinjaScript;
using NinjaTrader.NinjaScript.DrawingTools;

namespace NinjaTrader.NinjaScript.Indicators
{
    public class OilPriceApiSpotBasis : Indicator
    {
        private static readonly HttpClient Http = new HttpClient();
        private DateTime lastFetchUtc = DateTime.MinValue;
        private double spot = double.NaN;

        [NinjaScriptProperty]
        public string ApiKey { get; set; }

        [NinjaScriptProperty]
        public string Code { get; set; } // e.g. WTI_CRUDE_USD

        protected override void OnStateChange()
        {
            if (State == State.SetDefaults)
            {
                Name = "OilPriceApiSpotBasis";
                Code = "WTI_CRUDE_USD";
                IsOverlay = true;
                Calculate = Calculate.OnBarClose;
            }
        }

        protected override void OnBarUpdate()
        {
            // 30-minute throttle: 48 calls/day, free tier allows 50/day.
            if ((DateTime.UtcNow - lastFetchUtc).TotalMinutes >= 30)
            {
                lastFetchUtc = DateTime.UtcNow;
                FetchSpotAsync();
            }

            if (!double.IsNaN(spot) && CurrentBar > 0)
            {
                double basis = Close[0] - spot;
                Draw.TextFixed(this, "opa_spot",
                    string.Format("{0} spot {1:F2}  |  chart-minus-spot {2:+0.00;-0.00}",
                        Code, spot, basis),
                    TextPosition.TopRight);
            }
        }

        private async void FetchSpotAsync()
        {
            try
            {
                var req = new HttpRequestMessage(HttpMethod.Get,
                    "https://api.oilpriceapi.com/v1/prices/latest?by_code=" + Code);
                req.Headers.TryAddWithoutValidation("Authorization", "Token " + ApiKey);
                var resp = await Http.SendAsync(req);
                var body = await resp.Content.ReadAsStringAsync();
                // Response envelope: {"status":"success","data":{"price":82.13,
                //   "code":"...","currency":"USD","created_at":"..."}}
                var json = JObject.Parse(body);
                if ((string)json["status"] == "success")
                    spot = (double)json["data"]["price"];
            }
            catch (Exception e)
            {
                Print("OilPriceAPI fetch failed: " + e.Message);
            }
        }
    }
}

The 30-minute throttle is deliberate: 48 requests a day sits inside the free tier's 50-requests-per-day window, so the indicator runs indefinitely on a free key. The budget is per key, not per indicator: two instances doubles the calls, so give a second chart a slower throttle or a paid key. Paid tiers poll as often as their request budget allows.

2. Codes that pair with futures charts

Every code below is served by the same endpoint - swap the Code property on the indicator, or run several instances on one chart.

The interesting number is usually the difference, not the level: a CL chart with WTI spot drawn on it shows the physical premium or discount directly, and a Waha overlay on NG shows when the Permian basis detaches from Henry Hub - it has traded negative while the futures stayed positive.

3. EIA report days, without alt-tabbing

The weekly EIA petroleum status report (Wednesdays 10:30 ET) and natural gas storage report (Thursdays 10:30 ET) move CL and NG more than most technical levels. Our WTI and natural gas pages document how the physical series behave around those releases, and the same API serves EIA-derived series you can overlay the same way as the code above.

4. Want this as a packaged add-on instead of source code

We are gauging whether to ship a packaged NinjaTrader add-on - EIA report markers, spot overlays, and basis panels with no C# involved. If you would install that, tell us in one line. Enough hands raised is exactly how it gets built.