If you've ever built a website for Indonesian users and needed to show today's Hijri date, you probably know the pain. Most Hijri calendar APIs and libraries default to Umm al-Qura (Saudi Arabia's calendar), which can differ by a full day from what's actually observed and announced in Indonesia. It's not just a theoretical mismatch. In my own community, this got bad enough that nobody trusts online Hijri dates anymore. People just wait for the official government announcement instead of c...