poetry-charts

https://github.com/roboruby/poetry

Charts whose geometry is computed on the server (Ruby; d3-scale/d3-shape semantics, recharts' nice ticks) and shipped as finished SVG - no-JS valid, CSS-variable themed, zero client chart math. Stimulus chrome reads server-embedded coordinates for tooltips and legends; engines stay swappable behind a closed, versioned chart-spec (Chart.js reference adapter).