Architecture
Prepare for the mobile architecture round on iOS, Android and Flutter: module boundaries, dependency direction, state ownership and defending your pattern.
Question bank · no interactive practice yet
Flutter interview prep
Flutter loops often include a machine coding round: build a small working app in 60 to 90 minutes, then defend its structure. The questions after it are about state, rebuilds and what you would change for a team.
What the Flutter loop scores
| Round | What the interviewer writes down |
|---|---|
| Dart and async | Futures, streams, isolates and what runs on the UI thread. |
| State management | Why you chose the approach you did, and what it costs as the app grows. |
| Rendering and performance | Widget, element and render trees; what a rebuild costs; how you found jank. |
| Machine coding | A working feature in the time box, with a structure you can explain. |
| Platform integration | Platform channels, plugins and where native code is still the right answer. |
Loops differ by company. This is the common shape of senior loops, not a promise about any one employer.
The second question
Follow-ups that decide the round
“Your whole screen rebuilds when one counter changes. Fix it.”
Tests whether you understand rebuild scope, not only the state library.
“The JSON parse blocks the UI for 300 ms. What now?”
Tests whether you know when to reach for an isolate.
How to prepare, by the time you have
A week or less
Dart async, rebuild scope and your state management choice: be able to defend it in two minutes.
Two to four weeks
Work through the question bank by area, answering out loud first, then practise one machine coding task in 90 minutes.
Machine coding round
Time-box a small app, then explain its structure and what you would change for a team.
Prepare by round
The same rounds appear on every platform. Each page says what the round scores and which guides go deep.
Coding and live coding
Prepare for mobile coding, live coding and pair programming rounds: the tasks that recur, how they are graded, and what to say while you type.
Mobile system design
Prepare for the mobile system design round: offline behaviour, sync, caching, lifecycle and release, and what the interviewer scores at Senior and Staff.
Senior and Staff
What changes in a Senior or Staff mobile interview loop: the follow-up depth, the scope of the design round, and the evidence each level is expected to show.
Flutter interview guides
Flutter · 15 min
Flutter and Dart interview questions and answers
Flutter interview questions and answers on widgets, state, navigation and testing, plus Dart questions on async, the event loop and null safety.
Flutter · 10 min
Flutter architecture interview questions and costs
Flutter architecture interview questions on layering, state ownership, packages and testing, with the decision each one tests and what it costs a team.
Flutter · 12 min
Flutter machine coding interview: tasks and grading
What a Flutter machine coding interview asks, how the build is graded, and the state and structure choices that decide it before the UI is finished.
Flutter · 15 min
Senior Flutter interview questions and follow-ups
Twelve senior Flutter interview questions on rendering, keys, state, isolates, platform channels and architecture, with the follow-up to each.
Across platforms
Mobile system design · 17 min
Mobile system design interview: how the round is scored
How a mobile system design round runs, the seven things a senior answer covers, a worked offline sync example, and how Senior and Staff are scored.
Senior and Staff loops · 11 min
Mobile architecture interview questions, any platform
Architecture interview questions that do not depend on the platform: modules, shared code, server-driven UI, flags, old app versions and who owns what.
Live coding · 14 min
Mobile live coding interview: what to say while you type
How a mobile live coding round is scored, a 45-minute plan, what to say at each stage, a worked Swift example, and how to recover when you stall.
Practice
There is no interactive Flutter practice yet, and this site will not pretend there is. The question bank above is the honest starting point: answer each question out loud before you read the answer. How to practise without a tool.