Launching today
Codensity
Find the feature behind your software's carbon footprint
1 follower
Find the feature behind your software's carbon footprint
1 follower
Codensity shows the estimated carbon and energy of every feature in your Node.js app. Wrap a function with the SDK, and each feature gets its calls, energy and carbon by day, so you can see which one costs the most. Free plan to start.
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Hi Product Hunt, I'm Prince and I built Codensity.
I've been a developer for years, living in dashboards like Grafana and Prometheus: latency, error rates and throughput for every service. During my master's in informatics, focused on sustainability and software development, one question kept coming back: if we can measure everything else about our software, why can't we see the carbon behind it? Not for a whole server or cloud account, but for the features we actually ship.
The tools that do this are rarely built or priced for small and medium-sized teams. So I started building Codensity in February 2026, on my own until September, when a fellow developer joined me. Along the way it was selected as one of six finalists in a startup challenge at Innovatum Science Centre in Sweden.
How it works: you wrap the work you care about with the Node.js SDK. Codensity estimates the energy and carbon behind each feature and shows it by day, next to its calls. The first event creates the feature for you, so there's nothing to set up in the dashboard (PS, if you want to move fast. You can still set up anyway and use its ID).
What it makes visible:
- How often a feature runs isn't how much carbon it causes. In our demo, checkout is 14% of the calls but 34% of the carbon, because each call does far more work.
- Dormant features show up too, so dead code stops hiding.
- Carbon and calls on one timeline tell you whether a spike was more traffic or heavier work per call.
Every figure is an estimate, and the product labels it that way. It's built to compare features and spot changes over time, not for audited reporting.
There's a free plan to start (https://getcodensity.com/pricing), and you can explore a demo workspace without signing up: https://getcodensity.com/demo?re.... Node.js/Express and NestJS are supported today.
I'd love to hear from you, especially teams working on sustainability: which feature in your app would you measure first? I'll be here all day answering questions.