# Stream Chart

> A streamgraph: stacked layers flow around a wiggling centre line, drawn in left to right on view. A scrub line snaps to each period with a tooltip of every layer, the layer under the cursor lifts while the rest dim, and layers are directly labelled where they swell. Validated colorblind-safe palette, legend and screen-reader table included.

- Slug: `stream-chart`
- Category: [Charts](https://www.assembli.design/category/charts.md)
- Type: component
- Tags: streamgraph, stacked, time-series, svg, tooltip, interactive
- npm dependencies: motion
- shadcn/ui dependencies: none
- Added: 2026-10-15
- Live preview: https://www.assembli.design/preview/stream-chart
- Page: https://www.assembli.design/components/stream-chart

## Install

One-time setup (needs a subscription):

1. Add the registry to the project's `components.json`: `{"@assembli":{"url":"https://www.assembli.design/r/{name}.json","headers":{"Authorization":"Bearer ${ASSEMBLI_API_KEY}"}}}` (merge into `"registries"`).
2. Put an API key from https://www.assembli.design/account in `.env.local` as `ASSEMBLI_API_KEY=asm_…`.

Then install with the shadcn CLI (writes `components/stream-chart/stream-chart.tsx` and installs dependencies):

```bash
npx shadcn@latest add @assembli/stream-chart
```

Registry item JSON: https://www.assembli.design/r/stream-chart.json (send `Authorization: Bearer <api key>`)

## Code

> Component source needs an Assembli subscription ($12/month) and an API key sent as `Authorization: Bearer <key>`. To get one without copying anything, POST https://www.assembli.design/api/agent/login (or call the MCP tool connect_account), show the user the link it returns, and poll https://www.assembli.design/api/agent/token for the key. Or subscribe at https://www.assembli.design/pricing and create a key at https://www.assembli.design/account.