Travel API

Calculate CO2e emissions for passenger travel across flights, rail, car, bus, ferry, and taxi.

<div class="admonition admonition-tip"><span class="admonition-icon">💡</span><div class="admonition-content"><p>Complete Trip Emissions Pair the Travel API with the <a href="/docs/api/hotel">Hotel API</a> for complete business trip emissions (Scope 3 Category 6). Two calls — transport + accommodation — gives you the full picture.</p> </div></div>

Endpoint

<span class="api-method api-method-get">GET</span> /v1/travel/emissions

Parameters

Required Parameters

Parameter	Type	Description
`origin_country`	string	Origin country code (ISO 3166-1 alpha-2)
`destination_country`	string	Destination country code
`passengers`	integer	`1`

Optional Parameters

Parameter	Type	Default	Description
`origin_location`	string	-	Origin city or airport code
`destination_location`	string	-	Destination city or airport code
`transport_mode`	string	auto	`flight`, `rail`, `car`, `bus`, `ferry`, `taxi`
`return_trip`	boolean	`false`	Include return journey
`equivalents`	boolean	`false`	Include real-world equivalents

Flight Parameters

Parameter	Type	Default	Description
`cabin_class`	string	`economy`	`economy`, `premium_economy`, `business`, `first`

Car/Taxi Parameters

Parameter	Type	Default	Description
`vehicle_type`	string	`average`	`small`, `medium`, `large`, `average`
`vehicle_type`	string	`petrol`	`petrol`, `diesel`, `hybrid`, `phev`, `bev`

Example Request

curl "https://api.emissions.dev/v1/travel/emissions?\
origin_country=GB&\
origin_location=Edinburgh&\
destination_country=FR&\
destination_location=Lyon&\
transport_mode=flight&\
cabin_class=economy&\
passengers=1" \
  -H "Authorization: Bearer em_live_xxxxxxxxxxxx"

Example Response

{
  "data": {
    "type": "travel_emission",
    "id": "2214775f-b096-47df-88c9-6d4a17c97054",
    "attributes": {
      "emissions": {
        "co2e": 175.55,
        "co2e_unit": "kg",
        "co2e_calculation_method": "ipcc_ar6_gwp100",
        "per_passenger_kg": 175.55,
        "source_trail": [
          {
            "data_category": "emission_factor",
            "name": "Short-Haul Flight - Economy Class",
            "source": "DEFRA / ICAO",
            "source_dataset": "Greenhouse gas reporting: conversion factors 2025",
            "year": "2025",
            "region": "GB"
          }
        ]
      },
      "journey": {
        "passengers": 1,
        "return_trip": false,
        "mode": "flight",
        "cabin_class": "economy"
      },
      "route": {
        "total_distance_km": 1396,
        "transport_mode": "flight",
        "origin": {
          "input": "Edinburgh",
          "resolved": "City of Edinburgh, Scotland, United Kingdom",
          "lat": 55.9533,
          "lon": -3.1883
        },
        "destination": {
          "input": "Lyon",
          "resolved": "Lyon, France",
          "lat": 45.764,
          "lon": 4.8357
        }
      }
    }
  },
  "meta": {
    "methodology": "DEFRA 2025 / ICAO",
    "emission_factors_year": 2025,
    "includes_radiative_forcing": true,
    "calculated_at": "2026-02-07T14:30:00Z"
  }
}

Cabin Class Multipliers

Flight emissions vary significantly by cabin class:

Cabin Class	Multiplier	Example (1000km)
Economy	1.0x	125 kg
Premium Economy	1.6x	200 kg
Business	2.9x	362 kg
First	4.0x	500 kg

Location-Aware EVs

For electric vehicles (vehicle_type=bev or vehicle_type=phev), we calculate emissions using the origin country's electricity grid carbon intensity.

Country	Grid Intensity	100km EV Journey
Norway	26 g/kWh	0.54 kg CO2e
France	56 g/kWh	1.16 kg CO2e
UK	207 g/kWh	4.31 kg CO2e
Germany	350 g/kWh	7.28 kg CO2e
Poland	635 g/kWh	13.21 kg CO2e

<div class="admonition admonition-info"><span class="admonition-icon">ℹ️</span><div class="admonition-content"><p>Data source: Ember Climate Global Electricity Review 2025</p> </div></div>

Radiative Forcing

Our DEFRA 2025 emission factors for flights already include radiative forcing - the additional warming effect of emissions at high altitude. No separate multiplier is needed.

Transport Modes

Mode	Description
`flight`	Commercial aviation
`rail`	Train travel
`car`	Personal car
`bus`	Coach/bus
`ferry`	Passenger ferry
`taxi`	Taxi/rideshare

Complete Trip Emissions

Combine the Travel API with the Hotel API to calculate full business trip emissions:

// London → Tokyo business trip: flights + 4 nights hotel
const [travel, hotel] = await Promise.all([
  fetch('https://api.emissions.dev/v1/travel/emissions?' + new URLSearchParams({
    origin_country: 'GB',
    origin_location: 'London',
    destination_country: 'JP',
    destination_location: 'Tokyo',
    transport_mode: 'flight',
    cabin_class: 'business',
    return_trip: true
  }), { headers: { Authorization: `Bearer ${apiKey}` } }),

  fetch('https://api.emissions.dev/v1/hotel/emissions?' + new URLSearchParams({
    country: 'JP',
    nights: 4
  }), { headers: { Authorization: `Bearer ${apiKey}` } })
]);

const t = (await travel.json()).data.attributes.emissions;
const h = (await hotel.json()).data.attributes.emissions;

console.log(`Flights: ${t.co2e} kg CO2e`);
console.log(`Hotel:   ${h.co2e} kg CO2e`);
console.log(`Total:   ${t.co2e + h.co2e} kg CO2e`);
// Both endpoints report GHG Protocol Scope 3 Category 6