They are asking why, and you are answering what

A reader sent me the questions from a senior loop he had just sat. Fifteen of them, reconstructed from memory, which tells you he was thinking rather than panicking.

Look at the shape of the list.

Structs versus classes, taken to real depth. Why Apple introduced Swift Concurrency, not what it is. Escaping closures, and why we use them. Actor reentrancy, with a demand for a concrete example.

Every one of those is the same move. They were not testing whether he knew the feature. They were testing whether he understood the problem it exists to solve.

That is the question type that separates a senior loop from a mid one, and almost nobody prepares for it. You can memorise what an actor is in an afternoon. You cannot memorise why actors exist, because the answer is a story about the problem that came before them, and you either have that or you do not.

The good news is that it is preparable, and quickly.

Take the five features you would most likely be asked about. For each, write two sentences: what problem existed before this, and what it cost.

Actors exist because locks are correct and nearly impossible to keep correct as a codebase grows, and because data races are undetectable until they are catastrophic.

Escaping closures need the annotation because the compiler has to know whether a closure outlives the function call, which decides whether capture is safe and whether ARC needs to retain.

Structured concurrency exists because unstructured tasks leak. Work outlives the thing that needed it and nobody notices until the profiler shows it.

Two sentences each. Five features. That is one evening, and it changes how you sound on every question rather than on five of them.

The habit underneath it: when someone asks what something is, answer, then add the problem it solves. Unprompted. That single move reads as senior and it costs you nothing.

Questions answered at three levels, with the reasoning underneath: The iOS Interview Blueprint at salari.dev, or The Senior Signal for Android.

# The Brief, archive issues 6 to 10

Evidence and visibility. Undated.