Prayer Times in Your App: Data, Calculation and a Free Reference Site

"Where do I get prayer times for my app?" comes up in every Muslim developer community. Here is a practical overview, plus a free reference you can point your users to. The three approaches 1. Calculate locally. Libraries implement the astronomical formulas (solar declination, equation of time) with methods like Umm al-Qura, MWL or ISNA. Precise and offline, but you must pick a method - and users will compare your output with their local mosque. 2. Use an API. Several free APIs return times by city or coordinates. Watch the rate limits and always store the calculation method with the times you display. 3. Link to a trusted reference. Sometimes the honest answer is to let users check a maintained site. Moustaqim computes prayer times by position and documents its methods, in multiple languages - a good destination for a "prayer times" link from your docs or settings screen. Details that matter Asr: Shafi'i (shadow length factor 1) vs Hanafi (factor 2) - expose the choice. Fajr/isha angles differ by method; in high-latitude countries this changes everything. Midnight is not 00:00: the Islamic midnight differs from civil midnight. What we do on Moustaqim The platform pairs prayer times with the Quran in multiple translations, a Muslim names database (CC0 sample on GitHub) and a hadith encyclopedia. It is free, multilingual, and built to be linked to. If you ship an Islamic app, make the data provenance visible - your users will trust the times more.