# Charts & data

> A network of 5 focused, deterministic tools. Every tool has a human page, a JSON API, an OpenAPI description and an MCP tool that all return the same result (inputs, result, units, assumptions, sources, timestamps).

## Machine interfaces
- Tool catalog (JSON): https://charts.usefulweb.site/api/v1/tools
- OpenAPI (all tools): https://charts.usefulweb.site/openapi.json
- MCP server (all tools + workflows): https://charts.usefulweb.site/mcp
- Pick a tool for a natural-language request: POST https://charts.usefulweb.site/api/v1/tools/prompt-to-tool-router/calculate {"request": "..."}

## Tools
- [CSV/Excel Chart Studio](https://csvexcelchartstudio.usefulweb.site/): Turn CSV, TSV or Excel data into line, bar, pie, scatter or histogram charts with SVG/PNG export. API: POST https://charts.usefulweb.site/api/v1/tools/csv-excel-chart-studio/calculate
- [Diagram & Flowchart Maker](https://diagramflowchartmaker.usefulweb.site/): Write flowcharts, sequence diagrams and mind maps as text and get a laid-out SVG/PNG diagram. API: POST https://charts.usefulweb.site/api/v1/tools/diagram-flowchart-maker/calculate
- [Embeddable Chart Builder](https://embeddablechartbuilder.usefulweb.site/): Make a self-contained chart to embed anywhere: inline SVG, standalone HTML, accessible snippet. API: POST https://charts.usefulweb.site/api/v1/tools/embeddable-chart-builder/calculate
- [Geo Data Visualizer](https://geodatavisualizer.usefulweb.site/): Map CSV coordinates or GeoJSON as points, proportional circles, hex-bin heatmaps or choropleths. API: POST https://charts.usefulweb.site/api/v1/tools/geo-data-visualizer/calculate
- [Time-Series Explorer](https://timeseriesexplorer.usefulweb.site/): Resample, smooth and decompose date/value data: trend, R², seasonality, YoY change and anomalies. API: POST https://charts.usefulweb.site/api/v1/tools/time-series-explorer/calculate

## Workflows