The Emissions API
for Developers
Carbon footprint calculations for free. Production-ready, superfast CO2e REST API. No sales calls.
Built on verified data sources
Built for developers,
trusted by teams.
Everything you need to add carbon tracking to your product.
Blazing Fast
Sub-100ms responses globally. Built on edge infrastructure for consistent low latency.
Audit Ready
All factors are GHG Protocol compliant and expressed in CO₂e using IPCC AR6 GWP100. Full source trail in every response.
Developer First
Typed SDKs for TypeScript, Python & Go. OpenAPI spec. Copy-paste examples.
const { co2e } = await emissions.freight({
origin: "US", dest: "JP", kg: 500
});
Five APIs. One Platform.
One emissions calculator API covering freight, travel, hotels, electricity, and fuel combustion.
Freight API
Calculate CO2e for shipments across road, rail, sea, and air. Supports origin/destination geocoding, vehicle types, and fuel specifications.
- Road, rail, sea & air freight
- Route visualization, distance calculation
- Vehicle type & fuel granularity
- GLEC Framework compliant
# Calculate emissions for a US road shipment
$ curl "https://api.emissions.dev/v1/freight/emissions" \
-H "Authorization: Bearer em_live_xxx" \
-d "origin_country=US" \
-d "origin_location=Chicago" \
-d "destination_country=US" \
-d "destination_location=Houston" \
-d "weight=5000" \
-d "transport_mode=road"
# Response
"data": {
"type": "freight_emission",
"attributes": {
"emissions": {
"co2e": 156.78,
"co2e_unit": "kg"
},
"distance_km": 1764,
"transport_mode": "road",
"route": {
"transit_countries": ["US"],
"polyline": "axy~Fdi{uO..."
},
"ghg_protocol_scopes": {
"scope_3_category_4": 156.78
},
"methodology": "GLEC Framework v3.1"
}
}
}
Travel API
Emissions for travel including flights, rail, car, and bus. Per-passenger breakdowns with cabin class differentiation.
- Flights with cabin class multipliers (business, economy)
- Rail journeys (domestic & international)
- Car, taxi, bus & ferry modes
- Radiative forcing included for flights
// Calculate flight emissions SFO → NRT
const response = await fetch(
"https://api.emissions.dev/v1/travel/emissions" +
"?origin_country=US&origin_location=San+Francisco" +
"&destination_country=JP&destination_location=Tokyo" +
"&transport_mode=flight&cabin_class=business",
{ headers: { Authorization: `Bearer ${apiKey}` }}
);
// London → Paris: flight vs rail — which is greener?
const flight = await fetch(
"https://api.emissions.dev/v1/travel/emissions" +
"?origin_country=GB&origin_location=London" +
"&destination_country=FR&destination_location=Paris" +
"&transport_mode=flight&cabin_class=economy",
{ headers: { Authorization: `Bearer ${apiKey}` }}
);
// Flight response — 117.4 kg CO₂e
{
"data": {
"attributes": {
"emissions": {
"co2e": 117.4,
"co2e_unit": "kg"
},
"lifecycle_breakdown": {
"with_radiative_forcing": 117.4,
"without_radiative_forcing": 62.8
},
"ghg_protocol_scopes": {
"scope_3_category_6": 117.4
}
}
}
}
// Same trip by Eurostar — 4.8 kg CO₂e (96% less)
// transport_mode=rail → co2e: 4.8Hotel API
Accommodation emissions for 60+ countries. Factors vary 30x based on local energy grid — from 4.7 kg/night in Costa Rica to 152 kg/night in the Maldives.
- 60+ country-specific emission factors
- Compare destinations side-by-side
- DEFRA 2025 & Cornell benchmarks
- Scope 3 Category 6 compliant
// Calculate hotel emissions for a 5-night Singapore stay
const response = await fetch(
"https://api.emissions.dev/v1/hotel/emissions" +
"?country=SG&nights=5&rooms=1",
{ headers: { Authorization: `Bearer ${apiKey}` }}
);
// Response
{
"co2e": 186.5,
"co2e_unit": "kg",
"per_room_night_kg": 37.3,
"country_name": "Singapore",
"nights": 5,
"methodology": "DEFRA 2025 / Cornell CHSB Index"
}Electricity API
NewScope 2 emissions from electricity consumption. Supports 100+ countries, all 50 US states via EPA eGRID, and cloud provider regions.
- 100+ countries with Ember 2025 data
- US state-level via EPA eGRID 2023
- AWS, GCP & Azure cloud regions
- GHG Protocol Scope 2 dual reporting
# Calculate Scope 2 emissions — California office
import requests
response = requests.get(
"https://api.emissions.dev/v1/electricity/emissions",
headers={"Authorization": f"Bearer {api_key}"},
params={
"kwh": 10000,
"country": "US",
"state": "CA"
}
)
# Response
{
"co2e": 2112.2,
"co2e_unit": "kg",
"grid_intensity": 179,
"grid_intensity_unit": "gCO2e/kWh",
"source": "us_state",
"breakdown": {
"scope_2_location_based": 1790.0,
"scope_3_wtt": 322.2
}
}Fuel API
NewScope 1 emissions from direct fuel combustion. 16 fuel types including natural gas, diesel, LPG, and biofuels with gas-by-gas breakdown.
- 16 fuel types with DEFRA 2025 factors
- Gas-by-gas breakdown (CO₂, CH₄, N₂O)
- Well-to-Tank upstream emissions
- Biofuel-aware methodology
# Calculate emissions for office gas heating
$ curl "https://api.emissions.dev/v1/fuel/emissions" \
-H "Authorization: Bearer em_live_xxx" \
-d "fuel_type=natural_gas" \
-d "amount=15000" \
-d "unit=kwh"
# Response
{
"co2e": 3106.1,
"co2e_unit": "kg",
"fuel_label": "Natural Gas",
"breakdown": {
"direct_co2e": 2747.4,
"wtt_co2e": 358.5
},
"ghg_protocol_scopes": {
"scope_1": 2747.4,
"scope_3_category_3": 358.5
}
}Global coverage, local precision
Region-specific emission factors across 100+ countries. Not just averages — real local data.
Know exactly where
every number comes from
Most APIs return a number. We return the full audit trail — dataset name, source year, region, and compliance standards. Your auditor gets exactly what they need.
No extra calls, no separate documentation requests
Reproduce calculations for any reporting period
ISO 14083, GHG Protocol, EN 16258 flagged per response
Pricing
Simple, predictable pricing
Start free. Scale as you grow. No surprises.
or $45/mo monthly
For early-stage apps and startups finding their feet.
- All API endpoints
- Full response data
- Email support
- Usage analytics
or $90/mo monthly
For e-commerce, Shopify apps, and higher workloads.
- All API endpoints
- Full response data
- Email support
- Usage analytics
- 30% overage buffer
or $239/mo monthly
For scaling platforms with higher volume and batch processing.
- All API endpoints
- Full response data
- Priority support
- Usage analytics
- 40% overage buffer
- Batch processing (100/request)
Prices in USD. Need more volume? See all plans or contact us for Enterprise.
Frequently Asked Questions
Everything you need to know to get started.
Yes. Our APIs support worldwide coverage for all endpoints:
- Freight API — Calculates routes and emissions between any two locations globally. We use region-specific emission factors where available and fall back to internationally recognized defaults (GLEC Framework).
- Travel API — Supports all major airports (IATA codes), international rail networks, and car journeys in any country.
- Hotel API — Country-specific emission factors for 60+ countries with regional fallbacks for the rest.
- Electricity API — Grid intensity data for 100+ countries, all 50 US states, and major cloud provider regions.
- Fuel API — DEFRA 2025 emission factors applicable globally. Fuel combustion chemistry is consistent worldwide.
Rate limits depend on your plan:
| Plan | Requests/month | Rate limit |
|---|---|---|
| Free | 500 | 2 req/sec |
| Launch ($39/mo) | 5,000 | 5 req/sec (burst 10) |
| Starter ($79/mo) | 10,000 | 10 req/sec (burst 25) |
| Growth ($199/mo) | 50,000 | 15 req/sec (burst 40) |
| Scale ($499/mo) | 200,000 | 25 req/sec (burst 75) |
All responses include X-RateLimit-Remaining headers so you can track usage. Need higher limits? Contact us for Enterprise pricing.
We use internationally recognized emission factors and methodologies:
- GHG Protocol — The global standard for corporate carbon accounting
- GLEC Framework — Global Logistics Emissions Council for freight
- Ember 2025 — Global electricity grid intensity data
- US EPA eGRID — Sub-regional electricity grid factors for all 50 US states
- DEFRA 2025 — UK Government conversion factors, widely adopted internationally
- Cornell CHSB Index — Hotel sustainability benchmarks by country
Every API response includes a methodology field so you know exactly which factors were applied. Full documentation of our calculation methods is available in our methodology guide.
Yes. Our calculations are designed to be audit-ready and suitable for:
- Scope 1, 2 & 3 emissions reporting
- CDP (Carbon Disclosure Project) submissions
- SECR (Streamlined Energy and Carbon Reporting)
- CSRD (Corporate Sustainability Reporting Directive)
- Science Based Targets initiative (SBTi)
Every response includes a full source trail with dataset names, years, and regions — giving your auditor exactly what they need. For specific compliance requirements, we recommend consulting with your sustainability team.
Accuracy depends on the input data you provide:
- Basic inputs (origin, destination, weight) — We use average emission factors and calculated distances. Suitable for estimates and reporting.
- Detailed inputs (vehicle type, fuel, load factor) — Higher accuracy using specific emission factors for your exact scenario.
For freight, we calculate actual route distances using road/rail/sea networks rather than straight-line approximations. For electricity, we use sub-national grid data where available (US state-level, cloud regions) rather than country averages.
Yes! We provide official SDKs for popular languages:
- JavaScript/TypeScript —
npm install @emissions-dev/sdk - Python —
pip install emissions-dev - Go —
go get github.com/emissions-dev/go-sdk
All SDKs include full TypeScript types, automatic retries, and built-in rate limit handling.
We also provide an OpenAPI 3.0 specification so you can generate clients for any language.
The free tier includes:
- 500 API requests per month
- Access to all endpoints (Freight, Travel, Hotel, Electricity, Fuel)
- Full response data (no field restrictions)
- Community support via documentation
No credit card required. Perfect for side projects, testing, and building your proof of concept. Upgrade anytime when you need more capacity.
All requests require an API key. You can pass it in two ways:
# Option 1: Authorization header (recommended)
curl -H "Authorization: Bearer em_live_xxxxx" \
https://api.emissions.dev/v1/freight/emissions
# Option 2: X-API-Key header
curl -H "X-API-Key: em_live_xxxxx" \
https://api.emissions.dev/v1/freight/emissionsGet your API key instantly by signing up — no approval process required.
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Insights on carbon reporting, emissions data, and sustainability compliance.
