POST endpoint

If your chart is large or complicated, you may prefer to send a POST request rather than a GET request. This avoids limitations on URL length and means you don't have to worry about URL encoding. The /chart POST endpoint returns a chart. It takes the standard request parameters as a JSON object:

{
  "version": "2",
  "backgroundColor": "transparent",
  "width": 500,
  "height": 300,
  "devicePixelRatio": 1.0,
  "format": "png",
  "chart": {...}
}

tip

To include Javascript code in chart (e.g. to format labels), you must send chart as a string, not as a JSON object.

For examples of this, see documentation on using JS Functions.

---

Here is the type specification of the POST data object:

{
  width: string;                        // Pixel width
  height: string;                       // Pixel height
  devicePixelRatio: number;             // Pixel ratio (2.0 by default)
  format: string;                       // png, svg, or webp
  backgroundColor: string;              // Canvas background
  version: string;                      // Chart.js version
  key: string;                          // API key (optional)
  chart: string | ChartConfiguration;   // Chart.js configuration
}

ChartConfiguration is a Chart.js v2+ configuration object in JSON format.