Environment APIs
Free environmental APIs: carbon intensity and emissions data, renewable energy statistics, air and water quality, climate records and sustainability metrics.
15 tested APIs with full docs · 15 need no key · 21 more listed
Tested, with full documentation
We called each of these before publishing. Every page carries a working curl command, the real JSON response it returned, parameters and common errors.
UK Carbon Intensity
Free National Grid carbon intensity API with no key: current and forecast grid carbon per half hour, by region, with generation mix. Tested curl example.
Verified 19 Aug 2026
Environment Agency Flood Monitoring
Free UK flood API with no key: live flood warnings and alerts from the Environment Agency, with severity, affected area and river names. Tested example included.
Verified 21 Aug 2026
Energi Data Service
Free Danish energy API with no key: day-ahead electricity spot prices, production and consumption datasets from the national grid operator. Tested example included.
Verified 21 Aug 2026
EPA Envirofacts
Free US EPA Envirofacts API with no key: toxic release inventory, facility permits, air and water compliance data across US environmental programmes. Tested.
Verified 19 Aug 2026
Open-Meteo Flood
Free flood forecasting API with no key: daily river discharge forecasts worldwide from the GloFAS global flood model, with historical data back to 1984. Tested.
Verified 20 Aug 2026
GBIF
Free GBIF API with no key: 2 billion+ species occurrence records, taxonomic data and distribution maps from museums and research institutions worldwide. Tested.
Verified 19 Aug 2026
Global Warming API
Free climate data API with no key: global temperature anomalies from 1880 to now, plus CO2, methane, nitrous oxide and polar ice extent series. Tested example included.
Verified 21 Aug 2026
GrünstromIndex (Corrently)
Free German renewable energy forecast API with no key: hourly green-power share, wind and solar split, CO2 intensity and grid price by postcode. Tested example included.
Verified 21 Aug 2026
iNaturalist
Free iNaturalist API with no key: millions of citizen-science species observations with photos, coordinates, identifications and quality grades. Tested example.
Verified 19 Aug 2026
Kanari
Free wildfire API with no key: clustered satellite fire detections worldwide from VIIRS, GOES and MTG, with radiative power and a confidence grade. Tested example included.
Verified 21 Aug 2026
Luchtmeetnet
Free Dutch air quality API with no key: the official national monitoring network's stations and their measured and forecast pollutant concentrations. Tested example included.
Verified 21 Aug 2026
NESO Energy Data Portal
Free GB electricity data API with no key: the National Energy System Operator's open data catalogue over standard CKAN, covering demand, generation mix and carbon intensity. Tested example included.
Verified 21 Aug 2026
NOAA Tides & Currents
Free NOAA Tides and Currents API with no key: tide predictions, observed water levels, currents, water temperature and wind from US coastal stations. Tested.
Verified 20 Aug 2026
Open-Meteo Climate
Free climate projection API with no key: downscaled CMIP6 model data from 1950 to 2050 at 10 km resolution for any coordinates. Tested example and live response.
Verified 21 Aug 2026
USGS Water Services
Free USGS Water Services API with no key: real-time river discharge, gauge height, water temperature and groundwater levels from thousands of US sites. Tested.
Verified 19 Aug 2026
Choosing between these Environment APIs
Environmental APIs have grown quickly as carbon reporting became a regulatory requirement. Grid carbon intensity feeds are the most immediately useful — they let software schedule heavy work for when electricity is cleanest.
Much of this data comes from national grid operators and research bodies, which means it is open and citable but often regional rather than global in coverage.
More Environment APIs in the directory
21 further APIs in this category, of which 7 need no API key. These are catalogued from the public-API lists and link straight to each provider's own documentation — we have not tested them yet, so treat the auth and CORS flags as the upstream list's claim rather than ours. They are promoted to a full tested page as we work through them.
| API | What it does | Auth |
|---|---|---|
| 1ClickImpact | Environmental impact API for tree planting, carbon offsetting and ocean cleanup | KeyCORS |
| BreezoMeter Pollen | Daily Forecast pollen conditions data for a specific location | Key |
| Carbon Interface | API to calculate carbon (C02) emissions estimates for common C02 emitting activities | KeyCORS |
| Climatiq | Calculate the environmental footprint created by a broad range of emission-generating activities | KeyCORS |
| Cloverly | API calculates the impact of common carbon-intensive activities in real time | Key |
| CO2 Offset | API calculates and validates the carbon footprint | None |
| Danish data service Energi | Open energy data from Energinet to society | None |
| GrünstromIndex | Green Power Index for Germany (Grünstromindex/GSI) | NoneCORS |
| IQAir | Air quality and weather data | Key |
| National Grid ESO | Open data from Great Britain’s Electricity System Operator | None |
| OpenAQ | Open air quality data | Key |
| PM2.5 Open Data Portal | Open low-cost PM2.5 sensor data | None |
| PM25.in | Air quality of China | Key |
| PVWatts | Energy production photovoltaic (PV) energy systems | Key |
| Solematica | Compare Italian solar (photovoltaic) installer offers, energy prices (PUN/ARERA) and satellite roof data | None |
| Srp Energy | Hourly usage energy report for Srp customers | Key |
| SustainMetrics | 18,000+ GHG emission factors from DEFRA, EPA, ADEME, Ember | KeyCORS |
| Thames Water Open Data | Open Data from the UK's largest water and wastewater services company | Key |
| WattBuy | Electricity usage estimations, carbon footprint estimations, and utility data | KeyCORS |
| Website Carbon | API to estimate the carbon footprint of loading web pages | None |
| Website Carbon | API to estimate the carbon footprint of loading web pages | KeyCORS |
Turn API responses into results
Once the request works you still have to do something with what comes back. These run in your browser, free, with nothing uploaded.
JSON Formatter
Paste a raw response and read it indented, folded and colour-coded.
JSON Path Finder
Click any value to get the path that reaches it in your own code.
JSON to TypeScript
Turn a captured response into typed interfaces before you write the fetch.
CSV to JSON Converter
Turn a spreadsheet into the request body a POST endpoint expects.
Unix Timestamp Converter
Decode the epoch fields almost every API returns.
JWT Decoder
Read the claims and expiry inside a bearer token without pasting it anywhere.
PDF Table to CSV
Pull a table out of a PDF so it can be posted to an API as data.
Event Schema Generator
Publish what an API returns as structured data search engines can read.