Mobile & Web Interview questions

Flutter Developer interview questions

These Flutter Developer interview questions come from our vetting, where 3.4% of applicants pass 5 gates. You get 20 questions with answer hints, a task, red flags and a scorecard.

Updated: October 2026Remote Pro Ai · Mobile & Web20 questions

Build my squad

How we assess

Every applicant goes through 5 gates: application, an AI-assisted screen, a live technical assessment scored by a practice lead, a client-fit interview, and reference and credential checks. The questions below come from the live assessment. We score answers on reasoning and trade-offs, not on recalling definitions.

20 technical questions with model-answer hints

Questions 1–⁠10 (role-specific)

  1. How do you decide between Bloc and Riverpod for a new app?

    Model-answer hint

    Team size, testability, tolerance for boilerplate; documents the decision; no tribalism.

  2. What happens when setState is called high in a deep widget tree?

    Model-answer hint

    Rebuild scope, const constructors, splitting widgets, selectors to limit rebuilds.

  3. How do you make an app fully RTL-correct?

    Model-answer hint

    Directionality, EdgeInsetsDirectional, AlignmentDirectional, mirroring icons only where meaningful, tests in both locales.

  4. Where do you store an access token on the device?

    Model-answer hint

    flutter_secure_storage backed by Keychain / Keystore, never SharedPreferences; refresh handling.

  5. When do you write a platform channel?

    Model-answer hint

    No maintained plugin or a native-only SDK; covers method channels, error handling and threading.

  6. A long list janks while scrolling. What do you check?

    Model-answer hint

    ListView.builder, image caching, DevTools frame chart, expensive builds, isolates for heavy work.

  7. How do you implement deep links that survive a login screen?

    Model-answer hint

    App Links / Universal Links, router guards, storing the pending route, testing cold and warm starts.

  8. Describe your release pipeline.

    Model-answer hint

    Flavours, code signing, Codemagic or Fastlane, staged rollout, crash monitoring, versioning policy.

  9. How do you test a Flutter feature?

    Model-answer hint

    Unit tests for logic, widget tests, golden tests for Arabic layouts, integration tests on real devices.

  10. A national-ID login times out. What should the app do?

    Model-answer hint

    Clear message, retry path, clean session state, logging without personal data.

Questions 11–⁠20 (Mobile & Web core)

  1. How do you estimate a feature when requirements are still unclear?

    Model-answer hint

    break it down, name the unknowns, run a short spike, give a range and re-estimate as you learn.

  2. How do you integrate national-ID login such as Nafath or UAE Pass safely?

    Model-answer hint

    standard redirect or app-to-app flow, state and nonce checks, secure token storage, expiry and failure paths.

  3. What goes into your definition of done for a user-facing feature?

    Model-answer hint

    tests, accessibility checks, analytics events, error states, documentation, feature flag.

  4. How do you set and enforce a performance budget?

    Model-answer hint

    Core Web Vitals or startup targets measured on mid-range devices, with CI checks that fail on regression.

  5. How do you release safely to millions of users?

    Model-answer hint

    feature flags, staged rollout, crash and error monitoring, fast rollback, store review planning.

  6. How do you handle offline or unreliable connectivity?

    Model-answer hint

    local caching, optimistic updates with conflict handling, retries with backoff, clear user feedback.

  7. What do you check before an app starts handling payments?

    Model-answer hint

    PCI scope, tokenisation, idempotency, webhooks, reconciliation, provider sandbox tests.

  8. How do you keep dependencies and SDKs secure and current?

    Model-answer hint

    lockfiles, automated update pull requests, vulnerability scanning, licence checks, removing unused packages.

  9. A design cannot be built as drawn. What do you do?

    Model-answer hint

    early feasibility review, alternatives with trade-offs, design-system components, a shared decision with the designer.

  10. How do you review a colleague’s pull request?

    Model-answer hint

    correctness, readability, tests and security; small PRs; clear blocking versus non-blocking comments.

Interviewer tip: Ask for a real example after every answer. Strong candidates describe what they built, what broke and what they changed.

Practical task

90-minute live build in a provided Flutter starter. Implement a bilingual “service request” screen with form validation, an Arabic / English toggle that flips layout direction, a mocked API call with loading and error states, and secure storage of the returned token. Include 2 widget tests and one golden test in Arabic. Scored on architecture, RTL correctness, error handling and test quality.

How to run it Share the brief 24 hours ahead or run it live. Ask the candidate to talk through trade-offs as they work; reasoning matters more than a finished artefact.

Red flags our practice leads watch for

  • Stores tokens or personal data in SharedPreferences.
  • Hard-codes left and right padding and text alignment.
  • Cannot explain why a widget rebuilds.
  • Has never taken an app through App Store review personally.
  • Universal flag: Vague answers that never reach a concrete system, number or decision the candidate personally owned.

The scorecard we use

Score each dimension 1–⁠4 (1 = no evidence, 2 = partial, 3 = solid, 4 = exceptional):

DimensionWeightWhat a 4 looks like
Technical depth, production judgement and security40%Explains how and why, designs for failure and sensitive data, and knows each tool’s limits
Practical task and problem solving30%Delivers a working solution with tests and documented decisions
Communication and documentation20%Explains clearly to technical and non-technical audiences, in English or Arabic
References and regional context10%References confirm the claimed scope; knows the frameworks and data-residency rules that apply

Pass bar: weighted average of 3.0 out of 4 or higher, with no dimension below 2. The practice lead approves the final result.

Skip the interview loop

Every specialist on our shortlist has already passed this assessment. Working in 4 working days.

Frequently asked questions

Yes. The questions, hints, practical task and scorecard are free to use. They work best when every interviewer scores the same dimensions independently and compares notes afterwards. Ask for a concrete example after each answer, because recalled definitions say little about how someone performs on a live system.

They come from the same live technical assessment, but practice leads rotate and adapt questions so candidates cannot rehearse them. What stays fixed is the scope being tested, the practical task format and the scorecard, which is why the published version is safe to share.

Plan for a technical conversation covering 8 to 10 of the questions, plus the practical task either live or as a short take-home. Use the remaining questions as follow-ups. If you would rather skip the loop, Remote Pro Ai shortlists already-assessed specialists within 48 hours.

Our pass bar is a weighted average of 3.0 out of 4 or higher across the 4 dimensions, with no dimension below 2. Production judgement and security, scored inside the 40% technical dimension, often separate strong candidates from those who interview well but struggle once they own a live system.

The task mirrors the first week of real work in this role and never uses client data. It runs live or as a short take-home of a few hours, and the candidate then explains the trade-offs behind each decision. Reasoning and production habits count for more than a polished final artefact.