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Mobile App Development Interview Questions in Chennai

36 practice questions with answers for Mobile App Development interviews in Chennai.

Mobile App Development jobs in Chennai

Chennai is a long-standing IT-services and SaaS hub along OMR, with strong demand for testing, data and support-engineering roles. Many companies here hire freshers in large batches and train them on the job.

Below are 36 questions that match the mix of service, product and domain employers hiring junior mobile app developers in Chennai.

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01

How do you create reusable custom widgets in Flutter?

Dart and Flutter BasicsMedium
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Extract repeated UI into a StatelessWidget class with clear constructor parameters, rather than helper methods that return widgets, because classes get their own element, can be const and rebuild independently. Accept callbacks for events, use the theme for colours and text styles, and provide sensible defaults. Group them into a shared widgets folder or design system package and document them with widget previews or a showcase screen.
02

What is Metro?

React Native CoreMedium
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Metro is the JavaScript bundler for React Native. It resolves modules, transforms code with Babel, and serves the bundle to the app during development with Fast Refresh. For release builds, it produces a minified bundle that is compiled to Hermes bytecode. It supports platform-specific extensions, asset handling and configuration in metro.config.js for things like SVG transformers or monorepo setups with watch folders.
03

Why use TanStack Query for server state in mobile apps?

React Native Navigation, State and Native ModulesMedium
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Server state, such as data fetched from APIs, has caching, refetching, staleness and retry concerns that client state libraries do not handle well. TanStack Query caches responses by query keys, deduplicates requests, refetches on focus or reconnect, supports pagination and infinite queries, optimistic updates and offline persistence. It removes large amounts of useEffect and loading-state code and keeps screens consistent.
04

What is the freezed package used for?

Flutter State Management and ArchitectureMedium
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freezed generates immutable data classes with copyWith, equality, toString and union types or sealed classes, and integrates with json_serializable for fromJson and toJson. It removes boilerplate when modelling state such as loading, data and error variants. You annotate a class, run build_runner, and get generated code in a part file. With Dart 3 sealed classes and records, some teams need it less, but it is still widely used.
05

A screen re-renders every time the user types in a search box, making it laggy. How do you fix it?

React Native CoreMedium
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Keep the search text state local to the search input component so only it re-renders, debounce the query before updating the list or calling the API, and memoise the list and row components. Avoid storing frequently changing values in a global store that many components subscribe to. Use the React DevTools profiler to confirm which components render, and useDeferredValue to keep typing responsive.
06

Write an EAS configuration for development, preview and production builds.

App Store and Play Store PublishingMedium
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{ "cli": { "version": ">= 12.0.0" }, "build": { "development": { "developmentClient": true, "distribution": "internal" }, "preview": { "distribution": "internal", "channel": "preview" }, "production": { "autoIncrement": true, "channel": "production" } }, "submit": { "production": {} } }
07

Explain the StatefulWidget lifecycle methods.

Dart and Flutter BasicsMedium
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createState creates the State. initState runs once for setup like controllers and subscriptions; do not use inherited widgets there. didChangeDependencies runs after initState and when inherited data changes. build runs on every rebuild. didUpdateWidget runs when the parent rebuilds with new configuration. dispose runs when removed permanently, where you cancel streams, dispose controllers and timers to avoid memory leaks.
08

The API responses are slow on mobile networks. What can the mobile team ask the backend team to change?

Mobile Backend, APIs and FirebaseMedium
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Ask for pagination with sensible page sizes, gzip or brotli compression, removing unused fields or providing screen-specific endpoints, and aggregated endpoints to avoid multiple sequential calls. Request proper cache headers and ETags so the client can reuse responses. Ask for resized images through a CDN and HTTP/2 or HTTP/3 support. Share measured timings from real devices to justify the requests.
09

Write a React Native function that uploads an image with progress using Expo FileSystem.

Mobile Backend, APIs and FirebaseHard
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import * as FileSystem from 'expo-file-system'; export async function uploadImage(uri, token, onProgress) { const task = FileSystem.createUploadTask( 'https://api.example.com/upload', uri, { httpMethod: 'POST', uploadType: FileSystem.FileSystemUploadType.MULTIPART, fieldName: 'file', headers: { Authorization: `Bearer ${token}` }, }, ({ totalBytesSent, totalBytesExpectedToSend }) => onProgress(totalBytesSent / totalBytesExpectedToSend) ); const res = await task.uploadAsync(); if (res.status !== 200) throw new Error('Upload failed'); return JSON.parse(res.body); }
10

What is app signing and why must you protect the keys?

App Store and Play Store PublishingMedium
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Signing proves the app comes from you and that updates are from the same developer. On Android, you sign uploads with an upload key and Play App Signing re-signs with the app signing key held by the store; a lost upload key can be reset, but losing a self-managed app key meant you could never update the app. On iOS, signing uses certificates and provisioning profiles. Store keys in a secure vault and CI secrets, never in the repository.
11

How do you communicate a delayed release to stakeholders?

App Store and Play Store PublishingMedium
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I inform them as soon as I know, not on the release day. I explain the reason briefly, such as a store rejection or critical bug, the impact, the new estimated date, and what we are doing to avoid repeating it. I offer options, like releasing other features first. Regular short updates until release keep trust, and I note learnings in the release retrospective.
12

How do you balance speed and quality when a client wants features fast?

Mobile Development FundamentalsMedium
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I agree on what quality means for this release, such as no crashes in key flows, working offline basics and tests for payment logic. I deliver the smallest useful version first, behind feature flags if needed, and avoid shortcuts in areas that are expensive to fix later, like data models and security. I make technical debt visible in the backlog with an estimate so it is planned rather than forgotten.
13

Write a Riverpod provider that fetches data asynchronously and display it in a widget.

Flutter State Management and ArchitectureMedium
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final productsProvider = FutureProvider.autoDispose<List<Product>>((ref) { final repo = ref.watch(productRepositoryProvider); return repo.fetchProducts(); }); class ProductsView extends ConsumerWidget { const ProductsView({super.key}); @override Widget build(BuildContext context, WidgetRef ref) { final products = ref.watch(productsProvider); return products.when( loading: () => const Center(child: CircularProgressIndicator()), error: (e, _) => const Center(child: Text('Failed to load')), data: (items) => ListView(children: [for (final p in items) ListTile(title: Text(p.name))]), ); } }
14

Users get logged out randomly. The access token refresh seems to fail sometimes. What could be wrong?

Mobile Backend, APIs and FirebaseHard
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A common cause is a race condition: several requests receive 401 at once and each triggers a refresh, so later refreshes use an already rotated refresh token and fail, logging the user out. Fix it by allowing only one refresh at a time and queueing other requests until it completes, then retrying them with the new token. Also check device clock issues, token expiry settings and secure storage read failures.
15

How does the keyboard affect layouts in React Native and how do you handle it?

React Native CoreMedium
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When the keyboard opens it can cover inputs, especially at the bottom of the screen. Use KeyboardAvoidingView with behavior padding on iOS, and rely on Android's adjustResize window setting, or use react-native-keyboard-controller for consistent behaviour on both. Wrap forms in a ScrollView with keyboardShouldPersistTaps set to handled so buttons work while the keyboard is open, and dismiss the keyboard on submit.
16

What is hot reload and how is it different from hot restart?

Mobile Development FundamentalsEasy
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Hot reload injects changed code into the running app and rebuilds the UI while keeping the current state, so you see changes in about a second. Hot restart reloads the whole app code and resets state, needed when changing initialisation logic, global variables or app startup. React Native offers Fast Refresh, similar to hot reload. Native code changes, such as new plugins or platform files, require a full rebuild.
17

How do you test React Native components?

Testing, Performance and CI/CDEasy
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Use Jest as the test runner with React Native Testing Library, which renders components and queries them the way users do, by text, role or label. Fire events like fireEvent.press or userEvent, then assert on output. Mock native modules and network calls with jest mocks or MSW. For end-to-end tests on real builds, use Detox or Maestro, which drive the app on emulators and simulators.
18

Describe a time you had to deliver a feature with incomplete requirements.

React Native CoreMedium
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Situation: product asked for a referral feature with only a one-line description. Task: deliver in a sprint. Action: I listed open questions, met the product manager for 20 minutes to agree on core rules, built the agreed version with configurable reward values from the backend, and documented assumptions in the ticket. Result: we shipped on time, and later changes needed only config updates instead of a new release.
19

Write a Redux Toolkit slice for a cart.

React Native Navigation, State and Native ModulesMedium
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const cartSlice = createSlice({ name: 'cart', initialState: { items: [] }, reducers: { addItem(state, action) { const existing = state.items.find((i) => i.id === action.payload.id); if (existing) existing.qty += 1; else state.items.push({ ...action.payload, qty: 1 }); }, removeItem(state, action) { state.items = state.items.filter((i) => i.id !== action.payload); }, }, }); export const { addItem, removeItem } = cartSlice.actions; export const selectTotal = (s) => s.cart.items.reduce((t, i) => t + i.price * i.qty, 0);
20

Your team has no automated tests and frequent regressions. How would you introduce testing?

Testing, Performance and CI/CDMedium
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Start where bugs hurt most: write unit tests for business logic like pricing, validation and state transitions, and a few end-to-end smoke tests for login, checkout and payment flows with Maestro or integration tests. Run them in CI on every pull request so failures block merges. Require tests for bug fixes going forward. Show reduced regressions after a few sprints to build team support.
21

What is Dart and why does Flutter use it?

Dart and Flutter BasicsEasy
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Dart is a typed, object-oriented language created for client development. Flutter uses it because Dart supports JIT compilation for fast hot reload in development and AOT compilation to native machine code for fast release apps. Dart has sound null safety, async-await, isolates for concurrency, and a garbage collector optimised for many short-lived objects, which suits Flutter's frequent widget rebuilding.
22

How does Flutter render UI differently from React Native?

Mobile Development FundamentalsMedium
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Flutter draws every pixel itself using its own rendering engine, Impeller, onto a canvas, so widgets look identical across platforms and do not depend on native UI components. React Native maps components like View and Text to real native views, so the UI uses platform controls. Flutter gives pixel consistency and predictable performance; React Native gives native look and easier reuse of native view libraries, plus web developer familiarity with JavaScript.
23

Your web team wants to reuse React code in the mobile app. How much can realistically be shared?

React Native CoreMedium
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Business logic, API clients, validation, state management, types and utility hooks can be shared through a monorepo package. UI components usually cannot be shared directly because web uses DOM elements and mobile uses native components, unless you adopt React Native for Web or a universal design system. Navigation and storage differ too. Plan a shared core package and platform-specific UI to avoid forcing awkward compromises.
24

A React Native app shows a red screen error in development: Text strings must be rendered within a Text component. What does it mean?

React Native CoreEasy
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React Native requires every string to be inside a Text component. The error usually appears when a string or a number is placed directly inside a View, or when a conditional like {count && <Badge />} renders 0 as text when count is zero. Wrap text in Text and use explicit conditions like {count > 0 ? <Badge /> : null} so falsy values are not rendered as raw strings.
25

Write a go_router configuration with an auth redirect.

Flutter State Management and ArchitectureMedium
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final router = GoRouter( initialLocation: '/', refreshListenable: authNotifier, redirect: (context, state) { final loggedIn = authNotifier.isLoggedIn; final goingToLogin = state.matchedLocation == '/login'; if (!loggedIn && !goingToLogin) return '/login'; if (loggedIn && goingToLogin) return '/'; return null; }, routes: [ GoRoute(path: '/', builder: (_, __) => const HomePage()), GoRoute(path: '/login', builder: (_, __) => const LoginPage()), GoRoute( path: '/product/:id', builder: (_, state) => ProductPage(id: state.pathParameters['id']!), ), ], );
26

Write a FlatList that shows products with pull-to-refresh and infinite scroll.

React Native CoreMedium
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function ProductList({ items, loading, onRefresh, onEndReached }) { const renderItem = useCallback(({ item }) => <ProductRow product={item} />, []); return ( <FlatList data={items} keyExtractor={(item) => item.id} renderItem={renderItem} refreshing={loading} onRefresh={onRefresh} onEndReached={onEndReached} onEndReachedThreshold={0.5} ListEmptyComponent={!loading ? <Text>No products</Text> : null} /> ); }
27

A global Redux store causes the whole app to re-render on every small change. How do you fix it?

React Native Navigation, State and Native ModulesMedium
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Components are probably selecting large parts of state or creating new objects in selectors. Select only the fields each component needs with useSelector, memoise derived data with createSelector, and keep state normalised. Move server data to RTK Query or TanStack Query and local UI state back into components. Verify improvements with the React profiler, checking which components render after each action.
28

How do you secure Cloud Firestore data accessed directly from a mobile app?

Mobile Backend, APIs and FirebaseMedium
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Because the app talks to the database directly, security rules are the backend. Write rules that check request.auth for authentication and that users can read or write only their own documents, for example allow read, write: if request.auth.uid == userId. Validate fields and types in rules, never leave test mode rules open, and move sensitive operations like payments or role changes to Cloud Functions. Test rules with the emulator suite.
29

How do you reduce app size for Flutter and React Native apps?

Testing, Performance and CI/CDMedium
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Publish Android App Bundles so users download only their architecture and density resources. In Flutter, use --split-debug-info and --obfuscate, remove unused packages and fonts, compress images and use tree-shaken icons. In React Native, enable Hermes, R8 minification and resource shrinking, and remove heavy libraries. For both, analyse size with tools like flutter build --analyze-size or APK Analyzer and lazy-load large assets.
30

Write a simple counter using StatefulWidget and setState.

Dart and Flutter BasicsEasy
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class Counter extends StatefulWidget { const Counter({super.key}); @override State<Counter> createState() => _CounterState(); } class _CounterState extends State<Counter> { int _count = 0; @override Widget build(BuildContext context) => Column( mainAxisSize: MainAxisSize.min, children: [ Text('Count: $_count'), FilledButton( onPressed: () => setState(() => _count++), child: const Text('Add'), ), ], ); }
31

Store review is delaying your launch date. How do you plan releases to avoid this?

App Store and Play Store PublishingMedium
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Submit builds early, a few days before the planned date, and use manual release so you can publish the approved build at launch time. Ship the code behind a remote feature flag so the feature can be enabled on launch day without a new review. Keep a pre-approved build ready, follow store guidelines closely and include clear review notes and demo login details for reviewers.
32

After a release, crash reports show a spike only on one Android OS version. What steps do you take?

Testing, Performance and CI/CDMedium
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Pause the staged rollout to limit impact. Filter crash reports by OS version and device to find the top stack trace, and check behaviour changes for that version, such as permission, background or edge-to-edge rules. Reproduce on an emulator of that version, fix it, add a regression test and resume rollout with a hotfix. Add that OS version to the regular test device matrix.
33

What are the JS thread and UI thread in React Native and why do they matter?

React Native Navigation, State and Native ModulesHard
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JavaScript, including React rendering and business logic, runs on the JS thread, while the native UI thread draws views and handles touches. If the JS thread is busy with heavy computation or large re-renders, taps and JS-driven animations lag even though the UI thread is free. Keep heavy work off the JS thread, move animations to the UI thread with Reanimated, and split expensive tasks into smaller chunks.
34

Explain Row, Column, Expanded and Flexible in Flutter layouts.

Dart and Flutter BasicsEasy
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Row lays out children horizontally and Column vertically, with mainAxisAlignment and crossAxisAlignment controlling placement. Expanded forces a child to fill remaining space along the main axis, and Flexible lets a child take up to its share but be smaller. Using flex values divides space proportionally. A common error is an unbounded width or height, such as a ListView inside a Column without Expanded, which throws a layout exception.
35

How do you handle pressure when a production issue affects many users?

Mobile Backend, APIs and FirebaseMedium
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I stay calm and focus on reducing impact first: confirm the issue, communicate status to the team, and look for the fastest safe mitigation such as a remote config switch, server-side fix or pausing a rollout. Then I find the root cause, ship a proper fix and write a short postmortem. Clear, regular updates to stakeholders reduce panic and let others plan around the issue.
36

How would you test a Bloc or Riverpod notifier?

Flutter State Management and ArchitectureMedium
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Test business logic without widgets. For Bloc, the bloc_test package's blocTest builds the bloc with a fake repository, acts by adding events, and expects a list of emitted states. For Riverpod, create a ProviderContainer with overrides for repository providers, read the notifier, call methods and assert the state. Use mocktail for mocks and keep tests fast, deterministic and independent of the network.

Companies with offices in Chennai (3)

IT services

Infosys

Mobile App Development interview questions

  • 30 questions
  • 4 rounds

Bengaluru, Mysuru, Pune +2

View questions
IT services

TCS

Mobile App Development interview questions

  • 30 questions
  • 4 rounds

Mumbai, Chennai, Pune +2

View questions
IT services

Wipro

Mobile App Development interview questions

  • 30 questions
  • 4 rounds

Bengaluru, Hyderabad, Pune +2

View questions

Frequently asked questions

Which companies hire Mobile App Development professionals in Chennai?

Companies with large offices in Chennai include Infosys, TCS, Wipro. Use their company pages below to practise employer-specific sets.

Are Mobile App Development interviews in Chennai different from other cities?

The questions depend more on the company than the city. Chennai's mix of employers decides the style: Many companies here hire freshers in large batches and train them on the job

How do I find Mobile App Development jobs in Chennai?

Shortlist companies with Chennai offices, keep your CV focused on Mobile App Development projects, apply on company career pages and job portals with the Chennai filter, and practise the questions on this page before each interview.

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