About prayer times in Karachi
Sajjada uses the University of Islamic Sciences, Karachi calculation method by default, widely followed across Pakistan, Bangladesh and parts of India.
The five daily prayers
The five salah are the spine of a Muslim's day: Fajr before dawn, Dhuhr after the sun passes its zenith, Asr in the afternoon, Maghrib just after sunset, and Isha at night. Each is a window, you have until the next prayer begins to offer it, though earlier is always better.
Calculation method matters
Different parts of the Muslim world use different methods to determine Fajr and Isha, the times where the sun is below the horizon and angles vary. Local mosques in Pakistan typically follow the University of Islamic Sciences, Karachi method, which is what Sajjada uses by default for Karachi. You can switch to any of the other major methods (ISNA, Muslim World League, Umm al-Qura, and others) in the app's settings.
The qibla from Karachi
From Karachi, the qibla, the direction of the Kaaba in Mecca, can be found instantly with the Sajjada compass. The app uses your phone's magnetometer and calibrates against your current GPS position for accuracy.