DC Hub
Environment
Live data on data-center facilities, power markets, grid telemetry, and fiber infrastructure
No keyCORSHTTPS
Free Environment APIs
Free public APIs for environment, each one verified and kept up to date.
28 listed · 15 need no key · 12 work in the browser
GrünstromIndex
Environment
Green Power Index for Germany (Grünstromindex/GSI)
No keyCORS
Luchtmeetnet
Environment
Predicted and actual air quality components for The Netherlands (RIVM)
No keyCORSHTTPS
Open-Meteo
Environment
Global weather forecast API for non-commercial use
No keyCORSHTTPS
Open-Meteo Marine
Environment
Ocean wave height, swell, sea temperature and marine weather data
No keyCORSHTTPS
UK Carbon Intensity
Environment
The Official Carbon Intensity API for Great Britain developed by National Grid
No keyCORSHTTPS
WattFigure
Environment
US electricity rates by state, with appliance and EV charging running costs
No keyCORSHTTPS
CO2 Offset
Environment
API calculates and validates the carbon footprint
No keyHTTPS
Danish data service Energi
Environment
Open energy data from Energinet to society
No keyHTTPS
kanari
Environment
Real-time worldwide wildfire detections, water bomber tracking and open fire archive
No keyHTTPS
National Grid ESO
Environment
Open data from Great Britain’s Electricity System Operator
No keyHTTPS
PM2.5 Open Data Portal
Environment
Open low-cost PM2.5 sensor data
No keyHTTPS
Solematica
Environment
Compare Italian solar (photovoltaic) installer offers, energy prices (PUN/ARERA) and satellite roof data
No keyHTTPS
Website Carbon
Environment
Calculates website carbon emissions per page view using real-time tests. Provides endpoints for testing and manual calculations.
No keyHTTPS
ZipCheckup
Environment
U.S. drinking water quality data by ZIP code from EPA and 20+ federal sources
No keyHTTPS
Carbon Interface
Environment
API to calculate carbon (C02) emissions estimates for common C02 emitting activities
API keyCORSHTTPS
Climatiq
Environment
Calculate the environmental footprint created by a broad range of emission-generating activities
API keyCORSHTTPS
OpenAQ
Environment
Open air quality data
API keyCORSHTTPS
Srp Energy
Environment
Hourly usage energy report for Srp customers
API keyCORSHTTPS
SustainMetrics
Environment
18,000+ GHG emission factors from DEFRA, EPA, ADEME, Ember
API keyCORSHTTPS
AirVisual
Environment
Air quality and weather data
API keyHTTPS
BreezoMeter Pollen
Environment
Daily Forecast pollen conditions data for a specific location
API keyHTTPS
Cloverly
Environment
API calculates the impact of common carbon-intensive activities in real time
API keyHTTPS
GridHub
Environment
Live wholesale electricity prices and demand across 25 grid zones
API keyHTTPS
All 28 Environment APIs
- DC Hub
- GrünstromIndex
- Luchtmeetnet
- Open-Meteo
- Open-Meteo Marine
- UK Carbon Intensity
- WattFigure
- CO2 Offset
- Danish data service Energi
- kanari
- National Grid ESO
- PM2.5 Open Data Portal
- Solematica
- Website Carbon
- ZipCheckup
- Carbon Interface
- Climatiq
- OpenAQ
- Srp Energy
- SustainMetrics
- AirVisual
- BreezoMeter Pollen
- Cloverly
- GridHub
- IQAir
- PM25.in
- PVWatts
- WeatherStack
Free Environment APIs — common questions
Counts and timings below come from our own scheduled checks of this category.
How many free environment APIs are there?
We track 28 in this category, of which 20 responded at our last check. 15 of them need no API key.
Which environment APIs work without an API key?
15 of the 28 entries here need no credential. Filter this page by "no key" to see them, or browse the no-key collection for every keyless API across all categories.
Can I use these environment APIs in a browser app?
7 entries in this category need no key and return CORS headers, which is the combination that lets you call them straight from client-side JavaScript. The rest need a server or a proxy in between.
Which is the fastest free environment API?
Of the keyless options that responded at our last check, Open-Meteo was quickest at a median 67 ms. Speed is only one factor — coverage and licensing usually matter more — but it is measured here rather than claimed.
How do you know these APIs still work?
We call every listing on a schedule and record the status code, response time and whether CORS headers came back. Those results drive the badges on this page. Across the whole catalogue, 487 of 2,712 entries were not responding at the last full run, which is the sort of thing an unchecked list never tells you.