{
  "name": "Payload and upgrade-weight JSON endpoint",
  "description": "Returns cargo capacity, fluid weight, upgrade weight, loaded weight, remaining payload, hitch/pin estimate, and tow-vehicle payload warnings.",
  "publisher": {
    "name": "OffGridRVHub",
    "url": "https://www.offgridrvhub.com"
  },
  "source": {
    "endpoint": "https://www.offgridrvhub.com/tools/api/payload.json",
    "fullCalculator": "https://www.offgridrvhub.com/tools/payload-calculator",
    "assumptions": "https://www.offgridrvhub.com/tools/calculator-assumptions",
    "documentation": "https://www.offgridrvhub.com/tools/calculator-api"
  },
  "caveat": "This is a planning estimate for RV education and comparison. It is not electrical, plumbing, safety, or installation advice.",
  "input": {
    "rigType": "travel-trailer",
    "gvwrPounds": 9995,
    "uvwPounds": 7600,
    "listedCargoCapacityPounds": 1700,
    "freshWaterGallons": 40,
    "grayWaterGallons": 0,
    "blackWaterGallons": 0,
    "propanePounds": 40,
    "peopleAndPetsPounds": 350,
    "foodGearAndToolsPounds": 450,
    "upgradeItems": [
      {
        "name": "Lithium batteries",
        "pounds": 120,
        "quantity": 1
      },
      {
        "name": "Roof solar and brackets",
        "pounds": 90,
        "quantity": 1
      },
      {
        "name": "Inverter, cabling, and hardware",
        "pounds": 45,
        "quantity": 1
      },
      {
        "name": "Portable generator",
        "pounds": 50,
        "quantity": 1
      }
    ],
    "hitchWeightPercent": 13,
    "towVehiclePayloadPounds": 1800,
    "towVehicleCabCargoPounds": 450
  },
  "result": {
    "baseCargoCapacityPounds": 1700,
    "freshWaterWeightPounds": 334,
    "wasteWaterWeightPounds": 0,
    "propaneWeightPounds": 40,
    "fluidWeightPounds": 374,
    "upgradeWeightPounds": 305,
    "totalPlannedCargoPounds": 1479,
    "estimatedLoadedWeightPounds": 9079,
    "remainingPayloadPounds": 221,
    "usedPayloadPercent": 87,
    "gvwrMarginPounds": 916,
    "estimatedHitchWeightPounds": 1180,
    "towVehiclePayloadUsedPounds": 1630,
    "towVehiclePayloadRemainingPounds": 170,
    "towVehiclePayloadPercent": 91,
    "rigOverloaded": false,
    "towVehicleOverloaded": false,
    "tightPayload": true,
    "verdictTitle": "Payload is workable, but the margin is tight",
    "verdictDetail": "The entered plan uses about 87% of the available cargo capacity and leaves roughly 221 lb before axle, tire, and hitch checks.",
    "recommendedNextMove": "Weigh the loaded rig before adding more batteries, solar, tools, or water containers. Tight paper margin deserves real scale tickets.",
    "watchOuts": [
      "This is a planning estimate from sticker numbers and entered cargo. Confirm real loaded axle weights on a CAT scale before treating the result as safe.",
      "Sticker cargo capacity labels vary. Some account for full fresh water or propane differently, so read the exact label before double-counting fluids.",
      "Axle ratings, tire load range, wheel ratings, hitch receiver ratings, and weight-distribution setup can fail before GVWR math does.",
      "Fresh water is a major payload item here. Traveling with a partial tank can be the simplest way to recover margin when water is available near camp.",
      "Off-grid upgrades are heavy in aggregate. Batteries, solar hardware, inverter cable, tools, spares, and generator weight should be planned together."
    ]
  }
}