'¿Qué Haces?' Vs. '¿Qué Estás Haciendo?': the Linguistic Truth Behind the Expressions
English relies heavily on the present continuous tense. If you text a coworker at 2:00 PM asking, "What are you doing?", you might be asking about their immediate task, their evening availability, or simply saying hello. Spanish does not distribute grammatical duty the same way. The compound construction, formed by combining the verb estar with the gerund form haciendo, carries a strict aspectual weight.
When you ask someone ¿Qué estás haciendo?, you are asking about the mechanical action taking place at this precise second. If you walk into a kitchen and find your roommate attempting to fix a blender with a butter knife, you say ¿Qué estás haciendo?. It implies visual observation, interruption, or surprise. Using it out of nowhere over WhatsApp sounds less like a casual "what's up" and more like an interrogation. The recipient might wonder if they were caught doing something wrong.