Reading an answer and giving one are different skills. Practice here means saying the answer, finding the gap in it, and then taking the follow-up.
iOS and Android: Interview Runtime
For iOS and Android, Interview Runtime is the practice layer: interview answer practice where you speak first and the follow-up comes after, the way a real round runs. It is for engineers who have read enough and now need to hear where their own answer breaks. The free iOS sample shows how it works before you buy.
Flutter
There is no interactive Flutter practice yet, and many Flutter loops add a machine coding round. This question bank is for Flutter interview prep at any level from junior to Staff: answer each Flutter interview question out loud before you read the answer, then build one small app in 90 minutes and explain its structure. The answers are about choices, trade-offs and failure modes, which is what a senior round scores.
React Native
There is no interactive React Native practice yet. Senior React Native rounds test the JavaScript and native boundary, so practise saying where a problem lives before you answer it. This question bank is for React Native interview prep over days, not a single cram session, junior to Staff, with answers built around production depth and what the interviewer is asking.
Mock coding interview practice
Live coding interview practice works when it is scored, not when it is repeated. You can run a mock coding interview alone, with a recording and a scorecard, or with a partner who plays the interviewer.
Alone: record it and score the recording
Pick a practical task you have not solved before: search as you type, an image loader for a list, a paginated feed. Set a 45-minute timer, share your screen to nobody, and narrate as if someone were watching. Then watch the recording once, with this scorecard beside you:
Decomposition. Did you say the plan, the types and the hard part before you typed?
Correctness. Does the core work, including the stale result or the reused cell?
Communication. Count the silences longer than ten seconds. That count is the number to reduce.
Testing instinct. Did you trace the code with a concrete input and name the edge cases before saying "done"?
Write one line of evidence per heading, the way an interviewer would. Across several recordings, look for the gap that repeats. That is what to practise next.
With a partner: make them push back
Explain your design for a minute, then have your partner challenge every other decision: "Do you even need a cache?", "Why not fetch in the initialiser?", "Why that state type?". Answer each one by acknowledging the point, giving the trade-off, and asking what they would do. Then swap roles. Playing the interviewer teaches you what the notes look like from the other side.
Most live rounds are lost on narration and recovery, not on the algorithm. This book is for iOS engineers who know the material but lose signal while sharing their screen: live coding, code review and take-home rounds, practised as a mock coding interview alone or with a partner. It assumes you already know Swift; it is not a first Swift book.
What to practise on
The tasks that recur, and how each is graded, are in the iOS coding interview, Android coding interview and Flutter coding interview guides. What to say while you type is in the live coding guide. For iOS and Android, Interview Runtime above adds what a recording cannot: a rubric score on each answer and the follow-up question an interviewer would ask next.