Remote data

Keep the layout once and send only the values: {{data.path}} placeholders resolve on every platform from the app's data or from a URL the widget fetches itself.

Data (data, setWidgetData, source)

{{data.path}} reads a value: {{data.city}}, {{data.days.0.hi}}. Integers print as integers, whole floats as integers up to 1e21 (21.0 → 21), other numbers as the shortest decimal without an exponent; a missing value prints nothing. An object printed whole ({{data.obj}}) is JSON, but key order and escaping differ between platforms — don't rely on its exact text. Placeholders fill strings only (text, labels, URLs) — numeric fields such as progress.value stay literal.

Three layers, later wins per top-level key:

1. config.data — defaults in the config.
2. setWidgetData(widgetId, data) — the app updates values without resending the layout.
3. source — JSON the widget fetches itself.

await setWidgetConfig({
  data: { city: "London" },
  source: {
    url: "https://api.example.com/weather?city=London&lang={{locale}}",
    refreshMinutes: 30,
    headers: { Authorization: "Bearer …" },
  },
  small: { type: "text", content: "{{data.city}} {{data.temp}}°" },
}, undefined, "weather");

await setWidgetData("weather", { temp: 21 });

source rules: https:// only (http://localhost / 127.0.0.1 exactly for development; look-alike hosts are refused), GET or POST (body), response a JSON value up to 256 KiB (of UTF-8 bytes on desktop), refreshMinutes 15–1440 (default 30). The last good response is cached per placement; a failed fetch keeps it. url, header values and body may use only {{locale}} and {{instance}} (no {{data.…}}) (one request per placement, see Instances).