Swatch Time API Demo

Small, standalone demo showing how to use the Swatch Internet Time API. This demo is intentionally minimal and uses vanilla JavaScript + Bootstrap so it's easy to copy and adapt.

Endpoint: https://api.swatchtime.online/api/v1/current

• The demo shows a set of selectable fields that are sent as a comma-separated fields query parameter to the API.
• The rendered ?fields= text input element is read-only and updates as you check/uncheck boxes.
• Click the green Fetch API data button to retrieve data.
• The "Sample code to fetch API data" shows the exact query that is being sent to the API.
• The sample fetch code demonstrates a robust pattern: it checks resp.ok, returns resp.json() and includes a .catch() handler for errors.
• The Copy button copies the snippet to the clipboard and shows a short Bootstrap toast confirmation.
• The demo will display the raw JSON and a parsed, friendly view.

Usage:

• Open index.html in a browser.

• Or, run via a simple static web server:

python3 -m http.server 8000
# then load http://localhost:8000/swatch-api-demo in your browser

Additional Resouces:

https://github.com/swatchtime

License:

MIT

API Field Formats (canonical)

• swatch: string — beats with two-decimal centibeat precision (e.g. "123.45").
• whole: string — floored integer part of beats, zero-padded to 3 digits (e.g. "005", "123").
• rounded: string — nearest-integer beat, wrapped modulo 1000, zero-padded to 3 digits (e.g. 999.6 -> "000").
• time24 (BMT): string — 24-hour time derived from Biel Mean Time (e.g. "16:50:24").
• time12 (BMT): string — 12-hour time derived from Biel Mean Time (e.g. "04:50:24").
• ampm (BMT): string — "AM" or "PM" for the time12 field.
• date (BMT): string — Biel date in YYYY-MM-DD (e.g. "2025-11-27").

Note: Rounding and display (important)

When producing the swatch field with centibeat precision, implementors must avoid displaying 1000.00. This can happen if the raw beat (e.g. 999.995) is rounded to two decimals before wrapping. Use the following safe pattern:

const rawBeats = bielSeconds / 86.4;
let rounded = Math.round(rawBeats * 100) / 100;
if (rounded >= 1000) rounded = rounded - 1000;
const swatch = rounded.toFixed(2);

This keeps user-friendly rounding and ensures the beat display stays within 0.00–999.99.

• timestamp: string — ISO-8601 UTC instant (e.g. 2025-11-27T15:50:24.851Z) — use this for unambiguous UTC comparisons.

Implementation notes

• BMT (Biel Mean Time): the API's human-readable date/time fields (time24, time12, ampm, date) are presented in BMT — a canonical fixed offset of UTC+1 with no DST.
• Canonical computation (how swatch is derived):
  • Compute seconds since UTC midnight including milliseconds.
  • Add 3600 seconds (fixed offset for BMT) and wrap modulo 86400.
  • Divide by 86.4 (seconds per beat) to get beats.
  • swatch is the beats value formatted to two decimals (centibeats).
  • whole is the floored integer part of beats (zero-padded to 3 digits).
  • rounded is the nearest integer of beats, then wrapped modulo 1000 and zero-padded to 3 digits.
• Prefer timestamp when you need UTC or when comparing events across timezones.
• date, time24, and time12 are conveniences derived from the same Biel instant used to compute swatch, so they match the beat value.