@finchart/core

A headless financial chart engine you assemble yourself.

Install

pnpm add @finchart/core

• Core does the math, you do the pixels. createPlotModel runs without a DOM or a canvas and hands back a list of draw commands. Core knows nothing about the DOM — not at runtime, not in its types. Browser wiring (browserDeps + PlotBuilder) is a set of collaborators that @finchart/dom layers onto the same Plot, the way react-dom sits on react.
• Series (candle, line, histogram, area, baseline, bar), panes, a bar-index x-axis, real-time appends (updateLast), and computed nodes. Drawing tools and indicators live in their own packages.
• Every collaborator is injected — leave one out and that job simply doesn't happen, and it never enters your bundle.

import { createPlotModel, lineSeries } from "@finchart/core/headless";

// Turn showGrid off — otherwise the grid is drawLine too, so the first
// command you get back is a grid line, not your series.
const model = createPlotModel({
  size,
  series: { series: lineSeries(), data },
  config: { showGrid: false },
});
const [line] = model.commands().filter((c) => c.type === "drawLine");

Choose an import lane

• @finchart/core — application-facing chart, data, and built-in series APIs.
• @finchart/core/headless — the compact model-and-series entry for SSR, workers, and command snapshot tests.
• @finchart/core/authoring — custom Series, SeriesSpec, render, and plugin contracts. It is for library/extension authors, not ordinary chart setup.

All three are explicit entry points; the root remains supported for existing applications.

Support matrix

• Node 20.19+ — where the headless path (SSR, workers, tests) runs; CI runs that floor.
• Browsers — Chrome 98+ · Edge 98+ · Firefox 94+ · Safari 15.4+ (2022-03). The floor is set by structuredClone, Object.hasOwn, and Array.prototype.at, and no polyfills ship — bring your own if you need to support something older.
• The repository's own toolchain (Node 24.21+ · pnpm 12) is higher than this. That is the contributor's floor, not the consumer's.

Docs

• Style tokens — the full CSS variable table — theme.md
• The Plot contract — plot-contract.md
• Glossary — glossary.md
• Time zones and sessions — time-zones.md
• Migrating from lightweight-charts — migrating-from-lightweight-charts.md