Best Environment APIs in 2026

The top 15 of 30 free Environment APIs, ranked by how easy they are to start with (API key, HTTPS, CORS), how reliable they are in our daily health checks, and what developers rate them. kanari API takes the top spot.

Last tested Oct 24, 2026 · Rankings update daily

1
kanari API
Online · 527 ms
Real-time worldwide wildfire detections, water bomber tracking and open fire archive.
- No API key needed
- Callable from the browser (CORS)
- HTTPS
No authHTTPSCORS
2
Open-Meteo API
Online · 609 ms
Free weather API for non-commercial use.
- No API key needed
- Callable from the browser (CORS)
- HTTPS
No authHTTPSCORS
3
Sähkön hinta nyt API
Online · 1106 ms
Finnish and Nordic day-ahead electricity spot prices (15-minute), cheapest hours.
- No API key needed
- Callable from the browser (CORS)
- HTTPS
No authHTTPSCORS
4W
WattFigure API
Online · 712 ms
US electricity rates by state, with appliance and EV charging running costs.
- No API key needed
- Callable from the browser (CORS)
- HTTPS
No authHTTPSCORS
5
GridVigil API
Online · 1588 ms
Pressure scores, demand, generation mix and alerts for the 10 major U.S. power grids.
- No API key needed
- Callable from the browser (CORS)
- HTTPS
No authHTTPSCORS
6
Danish data service Energi API
Online · 867 ms
Open energy data from Energinet to society.
- No API key needed
- HTTPS
No authHTTPSCORS ?
7
UK Carbon Intensity API
Online · 869 ms
The Official Carbon Intensity API for Great Britain developed by National Grid.
- No API key needed
- HTTPS
No authHTTPSCORS ?
8
Carbon Interface API
Online · 873 ms
API to calculate carbon (C02) emissions estimates for common C02 emitting activities.
- Callable from the browser (CORS)
- HTTPS
apiKeyHTTPSCORS
9
GridHub API
Online · 767 ms
Live wholesale electricity prices and demand across 25 grid zones.
- Callable from the browser (CORS)
- HTTPS
apiKeyHTTPSCORS
10
PM2.5 Open Data Portal API
Online · 1110 ms
Open low-cost PM2.5 sensor data.
- No API key needed
- HTTPS
No authHTTPSCORS ?
11
Solematica API
Online · 719 ms
Compare Italian solar (photovoltaic) installer offers, energy prices (PUN/ARERA) and satellite roof data.
- No API key needed
- HTTPS
No authHTTPSNo CORS
12
SustainMetrics API
Online · 697 ms
18,000+ GHG emission factors from DEFRA, EPA, ADEME, Ember.
- Callable from the browser (CORS)
- HTTPS
apiKeyHTTPSCORS
13W
Website Carbon API
Online · 684 ms
API to estimate the carbon footprint of loading web pages.
- No API key needed
- HTTPS
No authHTTPSCORS ?
14
CO2 Offset API
Online · 1414 ms
API calculates and validates the carbon footprint.
- No API key needed
- HTTPS
No authHTTPSCORS ?
15
Luchtmeetnet API
Online · 1433 ms
Predicted and actual air quality components for The Netherlands (RIVM).
- No API key needed
- HTTPS
No authHTTPSCORS ?

Environment APIs compared

Top Environment APIs compared
API	API key	HTTPS	CORS	Uptime	Response	Rating
kanari	No	Yes	Yes	Up	527 ms	Not rated
Open-Meteo	No	Yes	Yes	Up	609 ms	Not rated
Sähkön hinta nyt	No	Yes	Yes	Up	1106 ms	Not rated
WattFigure	No	Yes	Yes	Up	712 ms	Not rated
GridVigil	No	Yes	Yes	Up	1588 ms	Not rated
Danish data service Energi	No	Yes	Unknown	Up	867 ms	Not rated
UK Carbon Intensity	No	Yes	Unknown	Up	869 ms	Not rated
Carbon Interface	Required	Yes	Yes	Up	873 ms	Not rated
GridHub	Required	Yes	Yes	Up	767 ms	Not rated
PM2.5 Open Data Portal	No	Yes	Unknown	Up	1110 ms	Not rated

More Environment APIs

Best Environment API FAQ

What is the best free Environment API in 2026?

Based on access, reliability and developer ratings, the top free Environment APIs right now are kanari API, Open-Meteo API and Sähkön hinta nyt API. kanari API ranks first. Rankings update daily from health checks of all 30 Environment APIs in the directory.

What is the best Environment API without an API key?

kanari API, Open-Meteo API and Sähkön hinta nyt API need no API key, so you can call them without signing up. 15 of the 30 ranked Environment APIs are keyless.

Which Environment API works from the browser?

kanari API, Open-Meteo API and Sähkön hinta nyt API support CORS over HTTPS, so front-end JavaScript can call them directly without a proxy.

How are these APIs ranked?

Each API gets a score from: no API key (+), HTTPS (+), CORS support (+), 30-day uptime and response time from our daily health checks, and ratings from developers on this site. APIs that failed three checks in a row are left out until they recover.