When I started building GreenCalculus — a carbon calculator platform for sustainability officers and CSRD compliance teams — the first decision wasn't which framework to use. It was whether to use one at all. I chose not to. Here's why, and what I built instead. The problem with frameworks for calculation tools Carbon calculators have a specific job: take a number in, multiply it by an emission factor, output a result in tCO₂e. That's it. The interaction model is: User selects fuel type User enters quantity User clicks Calculate Result appears instantly There is no routing. There is no global state. There is no component tree. There is no reason to ship 40kb of runtime to do three multiplications. React, Vue, and Svelte are excellent tools. They're the wrong tool for this job. What "zero dependencies" actually means No npm. No bundler. No node_modules. No build step.…