BigBasket Mobile App Development Interview Questions & Answers
Curated interview practice questions with answers. These are practice scenarios, not a verified list of past interview questions.
About BigBasket hiring for Mobile App Development roles
BigBasket is an Indian online grocery company, majority owned by the Tata Group, that delivers fruits, vegetables, staples and household products. It runs scheduled delivery and quick commerce services such as BB Now across many cities. Its Bengaluru technology and business teams hire software engineers, data analysts, data scientists, supply chain analysts and product managers.
For Mobile App Development roles, this BigBasket practice set focuses most on React Native Navigation, State and Native Modules (5), Mobile Development Fundamentals (4), Testing, Performance and CI/CD (4), React Native Core (4). It has 1 easy, 25 medium, 4 hard questions, so you can start easy and work up to the harder ones.
Company type
E-commerce & consumer tech
Headquarters
Bengaluru, India
Main India offices
Bengaluru
BigBasket Mobile App Development interview process
Online coding or analytics assessment
Technical round 1
Technical round 2 (design or case)
Hiring manager round
Typical pattern based on public candidate experiences. Rounds vary by role, team and year.
Solved for BigBasketStart practicing
3 QUESTIONS FREESign up to unlock the full question bank and track your progress.Unlock every question and answer, then continue practising company-wise and package-wise.
✓ 3 questions free • Unlock the rest in seconds
01
How would you structure the folder layout of a medium-sized cross-platform app?
Organise by feature rather than by type: features/auth, features/cart, features/profile, each containing UI, state logic and data code. Keep shared pieces in core folders such as core/network, core/storage, core/theme and core/widgets or components. Put configuration for environments separately. This keeps related code together, makes ownership clear and lets features be moved into packages later. Enforce the structure with lint rules and code review.
02
How do you reduce app size for Flutter and React Native apps?
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.
03
What questions would you ask before estimating a new mobile app project?
I would ask about target platforms and minimum OS versions, user types and key flows, design readiness, backend availability and API documentation, offline needs, payments, notifications, analytics, third-party SDKs, security or compliance requirements, languages to support, and release expectations including store accounts. I would also ask who maintains the app afterward. Then I break features into tasks, estimate with a buffer for store review and testing.
04
How do you avoid unnecessary rebuilds in a Flutter app with state management?
Rebuild only what depends on the changed data. Use selectors such as context.select, ref.watch(provider.select(...)) or BlocSelector to listen to one field, split big widgets into smaller ones, and use const constructors. Keep state objects immutable with proper equality so identical states do not trigger rebuilds. Use Flutter DevTools rebuild tracking to find widgets that rebuild more often than expected.
05
Write a Dart sealed class for API results and handle it with an exhaustive switch.
In Bloc, the UI adds events, the Bloc handles them with on<Event> handlers and emits new immutable states, and widgets rebuild with BlocBuilder or react with BlocListener. A Cubit is a simpler version where the UI calls methods directly and the Cubit emits states, without event classes. Use Cubit for straightforward logic and full Bloc when you need event transformations like debounce or detailed traceability.
07
Compare Redux Toolkit, Zustand and React Context for state in React Native.
Context is built in and fine for rarely changing values like theme or auth, but every consumer re-renders on change. Redux Toolkit gives a predictable global store with slices, middleware and excellent DevTools, suited to large teams, and RTK Query handles API caching. Zustand is small and simple, with selector-based subscriptions that limit re-renders. Server data is often better handled by TanStack Query than by any global store.
08
How do you set up multiple environments such as dev, staging and production in a mobile app?
Create build flavours on Android and schemes or configurations on iOS, each with its own app ID suffix, app name, icon and API base URL, so all can be installed side by side. In Flutter, use --flavor with --dart-define-from-file for config values; in React Native, use react-native-config or Expo app config with environment variables. Keep secrets out of the repo and set them in CI.
09
Write a custom hook that fetches data with loading and error states.
Use react-native-gesture-handler, which processes gestures on the native side, often with Reanimated for smooth animations. For swipe to delete, the Swipeable or ReanimatedSwipeable component renders action buttons behind a row. Define gestures with the Gesture API, such as Gesture.Pan, and compose them when needed. Wrap the app root in GestureHandlerRootView. Provide an accessible alternative like a long-press menu for screen reader users.
11
How do you secure Cloud Firestore data accessed directly from a mobile app?
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.
12
A global Redux store causes the whole app to re-render on every small change. How do you fix it?
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.
13
How do you handle pressure when a production issue affects many users?
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.
14
How do animations work in React Native and why use Reanimated?
The built-in Animated API can run animations on the native thread with useNativeDriver for transform and opacity, but not for layout properties. Reanimated runs animation logic in worklets on the UI thread, so animations stay smooth even if JavaScript is busy, and supports gestures, layout animations and shared element transitions. Combined with react-native-gesture-handler, it is the standard for complex interactive animations.
15
The API responses are slow on mobile networks. What can the mobile team ask the backend team to change?
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.
16
Write an EAS configuration for development, preview and production builds.
Keys help Flutter match widgets to existing elements and state when the widget list changes. Without keys, Flutter matches by type and position, so reordering or removing items in a list of stateful widgets can attach state to the wrong item. Use ValueKey with a unique ID for list items, UniqueKey to force recreation, and GlobalKey rarely, for accessing state across the tree such as a Form.
18
How do you set up CI/CD for a cross-platform mobile app?
On every pull request, run lint, formatting checks, unit and widget or component tests. On merge, build signed Android and iOS release artifacts using CI services such as GitHub Actions, Codemagic, Bitrise or EAS Build, with signing keys stored as secrets. Use fastlane or EAS Submit to upload to internal testing tracks and TestFlight. Automate version numbers, generate release notes and run smoke tests with Maestro.
19
How do you decide which devices to test on for an Indian user base?
Use analytics from the existing app or market data to identify the most common manufacturers, OS versions, screen sizes and RAM levels among your users. Cover a budget device with 3 to 4 GB RAM, a mid-range phone, a recent flagship, an older OS version you still support, and at least one iPhone and tablet. Use cloud device farms for wider coverage and add devices that generate many crashes.
20
The client wants the app to look exactly like iOS on iPhones and like Material on Android. How do you approach this in a cross-platform app?
Identify which elements truly need platform-specific behaviour: navigation transitions, back gestures, date pickers, switches and dialogs. In Flutter, use adaptive constructors like Switch.adaptive or Cupertino widgets based on Theme.of(context).platform. In React Native, many components are native already, and Platform.select handles differences. Keep shared business logic and most layout common, and limit platform branches to a component library so they stay manageable.
21
Parsing a 10 MB JSON file freezes the Flutter UI for two seconds. How do you fix it?
JSON decoding is CPU-bound and runs on the main isolate, blocking frames. Move it to a background isolate with Isolate.run(() => parseProducts(jsonString)) or compute. Also consider whether the API can paginate or return less data, and parse lazily. Test in profile mode with DevTools performance view to confirm the frame time improvement, since debug mode exaggerates slowness.
22
Write a Dart HTTP client using dio with an interceptor that adds an auth token.
Release to internal testers and beta users first and collect feedback. Then roll out to 5 percent of production users, monitoring crash-free rate, ANRs, key conversion metrics and reviews for a few days, before moving to 20, 50 and 100 percent. Keep the redesign behind a remote flag to switch back without a release. Define rollback criteria in advance and communicate the plan to support teams.
26
Your app needs a third-party SDK that has only native Android and iOS libraries. How do you integrate it in React Native?
First check whether a maintained wrapper package exists. If not, create a native module using the Expo Modules API or a TurboModule with a typed spec, add the SDK through Gradle and CocoaPods or Swift Package Manager, and expose a small JavaScript API with promises and events. If using Expo, write a config plugin to apply native setup during prebuild. Test on both platforms and document the setup.
27
A React Native list of 2000 items scrolls slowly and shows blank areas. How do you fix it?
Use FlatList or FlashList rather than ScrollView with map. Provide a stable keyExtractor, memoise row components with React.memo, avoid inline functions and heavy computation in renderItem, and use getItemLayout or fixed item sizes where possible. Tune windowSize and maxToRenderPerBatch, compress and cache images with a library like expo-image, and test a release build, since dev mode is much slower.
28
Integration tests pass locally but fail randomly in CI. How do you make them reliable?
Flaky tests usually come from timing assumptions, shared state, network dependence or slow emulators. Replace fixed delays with waiting for specific conditions, mock or stub network calls with predictable responses, reset app data between tests, and use stable selectors like keys or test IDs instead of text that changes. Give CI emulators enough resources, retry only as a temporary measure, and track flaky tests separately to fix them.
29
A user reports that they cannot find your app in the store on their old phone. Why could this happen?
The app may not be available for their device because the minimum OS version is higher than theirs, the device lacks a required hardware feature declared in the manifest, the app is not released in their country, or the device architecture is excluded. Check the device catalogue in Play Console and the deployment target on iOS. Decide whether supporting that segment is worth lowering requirements.
30
Why is TypeScript recommended for React Native projects?
TypeScript adds static types to JavaScript, catching mistakes like wrong prop names, missing fields in API responses and undefined values at compile time. It improves editor autocomplete and makes refactoring safer in large codebases. New React Native and Expo templates use TypeScript by default, and Codegen for TurboModules and Fabric components uses typed specs. Combined with strict mode, it significantly reduces runtime crashes.
Tips to crack the BigBasket Mobile App Development interview
Practise DSA for engineering roles, and SQL plus Excel for analyst roles, as these are commonly tested in screening.
Think through grocery supply chain problems like demand forecasting, inventory freshness and delivery slot planning before case rounds.
Use the BigBasket app and note improvement ideas, which helps in product sense and why-BigBasket discussions.
Keep a one-minute story ready for every project on your CV: problem, your part, tools, result.
Practise the hard questions on this page aloud; BigBasket interviewers usually ask follow-ups on your first answer.
Frequently asked questions
How many rounds are there in the BigBasket Mobile App Development interview?
Candidates usually go through 4 stages: Online coding or analytics assessment; Technical round 1; Technical round 2 (design or case); Hiring manager round. The exact rounds change with the role, team, location and your experience, so confirm the process with the recruiter.
Which topics should I prepare for the BigBasket Mobile App Development interview?
This practice set leans on React Native Navigation, State and Native Modules (5), Mobile Development Fundamentals (4), Testing, Performance and CI/CD (4), React Native Core (4). Revise those first, then practise explaining one or two of your own projects end to end, because most BigBasket interviewers ask you to walk through real work.
Are these the exact questions asked at BigBasket?
No. These are curated practice questions that match the skills and difficulty usually tested in e-commerce & consumer tech interviews like BigBasket's. They are not a leaked or verified list of past questions.
Where does BigBasket hire Mobile App Development professionals in India?
BigBasket has large teams in Bengaluru. Openings and locations change often, so check the BigBasket careers page and filter by city and experience.
Mobile App Development questions for similar companies