Open Source · Standards-aligned

The green measurement tool for developers

Lightweight, pluggable carbon measurement that fits right into your IDE, CI pipeline, and cloud stack. Know your software's carbon footprint — without adding to it.

<2ms Overhead
SCI ISO/IEC 21031
GSF Aligned
carbonah — ~/my-app
$ carbonah measure --unit request
 
# Scanning project...
● Energy per request ........ 0.042 kWh
● Grid intensity ............ 285 gCO₂/kWh
● Embodied share ............ 0.8 mgCO₂
 
SCI Score: 12.8 gCO₂eq / request
 
▲ Tip: Shifting this workload 2h later
would reduce SCI by 18% (grid forecast:
234 gCO₂/kWh at 14:00 UTC)

Built to measure, not to bloat

Five principles guide everything we build. If the tool itself becomes a carbon aggressor, it defeats the purpose.

Measure, Don't Bloat

Adds negligible overhead to builds, tests, and runtime. If you can't feel it, it's doing its job.

Plug In, Don't Rewrite

Works with your existing codebase, CI/CD pipelines, IDEs, and cloud platforms. Zero code changes required.

Actionable, Not Academic

Scores, trends, and concrete suggestions you can act on today — not a 40-page report you'll never read.

Standards-Aligned

Built on the GSF's SCI specification (ISO/IEC 21031:2024) and compatible with the Impact Framework ecosystem.

Open Source

Community-driven, vendor-neutral, and transparent. Audit the code, contribute features, extend the plugins.

Real-Time & CI-Time

Get carbon scores while you code and as part of every pull request. Shift left on sustainability.

Three pillars of green software

Carbonah is built around the Green Software Foundation's three pillars for reducing software carbon emissions.

01 — ENERGY

Energy Efficiency

Measures energy consumed per functional unit — per API call, per build, per test run. Understand exactly where your compute energy goes and find the hotspots worth optimizing.

02 — CARBON

Carbon Awareness

Integrates real-time grid carbon intensity data to score when and where your workloads run. Shift compute to cleaner times and regions automatically.

03 — HARDWARE

Hardware Efficiency

Accounts for the embodied carbon of the infrastructure you're using. The greenest server is the one that's already been manufactured — Carbonah helps you use it wisely.

Software Carbon Intensity

Carbonah computes the SCI score defined in ISO/IEC 21031:2024 — a standardized way to measure and compare the carbon efficiency of software systems.

E Energy consumed by the software, measured in kWh
I Carbon intensity of the electricity grid, in gCO₂/kWh
M Embodied carbon share of the hardware being used
R Your functional unit — per request, user, build, or minute
SCI = (O + M) / R
O = E × I operational emissions
M = TE × TS × RS embodied share
R = functional unit per request, user…
ISO/IEC 21031:2024

Up and running in minutes

Carbonah fits into your workflow, not the other way around.

1

Install

One command. Works with npm, pip, brew, or as a standalone binary. Under 5 MB.

2

Configure

Point Carbonah at your project and choose your functional unit. A single YAML file does it.

3

Measure

Run locally in your IDE or plug into CI. Get SCI scores on every build and pull request.

4

Improve

Follow actionable tips, track trends over time, and set carbon budgets for your team.

Start measuring today

Join developers who care about the carbon footprint of the software they ship.

$ npm install -g carbonah