Short answer

API and embeddable week widget

Documented JSON endpoints and a tracker-free ISO week widget.

Short answer

The API validates every input and returns stable error codes; the widget uses no third-party fonts.

How it works

CORS is restrictive by default and the full contract is available as OpenAPI.

REST API v1

CORS is restrictive by default and the full contract is available as OpenAPI.

OpenAPI 3.1 JSON Widget

fetch("https://kalenderwoche.info/api/v1/week-from-date?date=2026-08-05")
  .then(response => response.json())