Abstract
<jats:p>STEMKit is a suite of 18 browser-based tools for computational chemistry and scientific data analysis, built on @stemkit/core, a JavaScript library of parsing and numerical routines with no DOM dependency. All computation runs inside the user’s own browser: nothing is transmitted, no account is required and nothing is installed, so the tools stay usable for unpublished or confidential data. The same modules run under Node.js, so an interactive analysis can be captured as a version-pinned script. The 16 domain modules carry 1077 tests validated against SciPy, NumPy and physical invariants rather than against the implementation itself. That validation exposed four defects that had been altering reported results, among them p-values floored at zero and the mass of haem iron taken as fluorine’s. All four are corrected and covered by regression tests.</jats:p>