Freight carbon: CO2e for road/rail/sea/air shipments by weight × distance, single-leg or m

[
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0xdCA14e2B0F7995fe9263d77A9E7dCd128D1E6dD7",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "3000",
    "maxTimeoutSeconds": 300
  }
]

{
  "bazaar": {
    "info": {
      "input": {
        "body": {
          "destination": "SGSIN",
          "mode": "sea",
          "origin": "GBSOU",
          "weight_kg": 20000
        },
        "bodyType": "json",
        "method": "POST",
        "type": "http"
      },
      "output": {
        "example": {
          "co2e_kg": 1520.44,
          "co2e_tonnes": 1.52044,
          "factor": {
            "source": "IMO GHG Study",
            "unit": "kgCO2e/tonne.km"
          },
          "route": {
            "distance_km": 15320.5,
            "tonne_km": 306410
          }
        },
        "type": "json"
      }
    },
    "schema": {
      "$schema": "https://json-schema.org/draft/2020-12/schema",
      "properties": {
        "input": {
          "additionalProperties": false,
          "properties": {
            "body": {
              "properties": {
                "destination": {
                  "description": "UN/LOCODE, IATA, name, or destination_lat + destination_lon",
                  "type": "string"
                },
                "legs": {
                  "description": "For multi-leg: array of { mode, origin, destination } (omit top-level mode/origin/destination)",
                  "type": "array"
                },
                "mode": {
                  "description": "sea | road | rail | air",
                  "type": "string"
                },
                "origin": {
                  "description": "UN/LOCODE, IATA, name, or origin_lat + origin_lon",
                  "type": "string"
                },
                "weight_kg": {
                  "description": "Shipment weight in kg (>0)",
                  "type": "number"
                }
              },
              "required": [
                "weight_kg"
              ]
            },
            "bodyType": {
              "enum": [
                "json",
                "form-data",
                "text"
              ],
              "type": "string"
            },
            "method": {
              "enum": [
                "POST"
              ],
              "type": "string"
            },
            "type": {
              "const": "http",
              "type": "string"
            }
          },
          "required": [
            "type",
            "method",
            "bodyType",
            "body"
          ],
          "type": "object"
        },
        "output": {
          "properties": {
            "example": {
              "type": "object"
            },
            "type": {
              "type": "string"
            }
          },
          "required": [
            "type"
          ],
          "type": "object"
        }
      },
      "required": [
        "input"
      ],
      "type": "object"
    }
  }
}

curl "https://api.myco2suite.io/api/v1/freight"
# -> 402 Payment Required, accepts[] lists how to pay
# retry with a PAYMENT-SIGNATURE (or PAYMENT header) once paid

const res = await fetch("https://api.myco2suite.io/api/v1/freight");
if (res.status === 402) {
  const { accepts } = await res.json();
  // pay one of accepts[] via an x402 client, then retry with the payment header
}

import httpx
res = httpx.get("https://api.myco2suite.io/api/v1/freight")
if res.status_code == 402:
    accepts = res.json()["accepts"]
    # pay one of accepts[] via an x402 client, then retry with the payment header