Dream11 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 Dream11 hiring for Mobile App Development roles
Dream11 is an Indian sports technology platform and the flagship brand of Dream Sports, which also includes FanCode and other businesses. Its engineering and analytics teams build systems that handle very high traffic during live matches. It hires for software engineers, SDETs, data engineers, data analysts and data scientists.
For Mobile App Development roles, this Dream11 practice set focuses most on Testing, Performance and CI/CD (7), Mobile Backend, APIs and Firebase (5), Flutter State Management and Architecture (4), React Native Navigation, State and Native Modules (4). It has 2 easy, 21 medium, 7 hard questions, so you can start easy and work up to the harder ones.
Company type
Product
Headquarters
Mumbai, India
Main India offices
Mumbai
Dream11 Mobile App Development interview process
Online assessment or assignment
Technical round 1
Technical round 2 (design or case)
Hiring manager round
Culture fit round
Typical pattern based on public candidate experiences. Rounds vary by role, team and year.
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01
How do you detect and fix memory leaks in cross-platform apps?
Leaks usually come from subscriptions, timers, controllers and listeners that are never disposed, or global caches that grow without limits. In Flutter, dispose controllers and cancel stream subscriptions in dispose, and check the DevTools memory view for growing instances. In React Native, return cleanup functions from useEffect and remove event listeners. Repeatedly open and close a screen while profiling to confirm memory returns to baseline.
02
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.
03
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.
04
Your app works on Android but crashes immediately on iOS when the user taps the camera button. What is the likely cause?
The most common cause is a missing NSCameraUsageDescription key in Info.plist. iOS terminates the app when it requests a protected resource without a usage description string. Add descriptions for camera, photo library, microphone and location as required by the plugin, written clearly for the user. Also verify the plugin's iOS setup steps, run pod install, and test on a real device since simulators lack cameras.
05
The cart total shows stale values on the checkout screen after items are removed on the cart screen. How do you fix it?
Each screen probably holds its own copy of cart data. Move cart state into a single shared state object, such as a Riverpod notifier or a Cubit provided above both screens, and have both screens watch it. All mutations go through that object, which emits a new immutable state. Derived values like total should be computed from the state, not stored separately, so they can never become inconsistent.
The app registers with the platform push service, FCM on Android and APNs on iOS, often both through FCM, and receives a device token. The app sends this token to your backend, linked to the user. When an event happens, the backend sends a message to FCM or APNs with the token, which delivers it to the device. The app requests notification permission, handles taps to open the right screen, and refreshes tokens when they change.
07
Two users editing the same shared list offline create conflicting changes. How do you resolve conflicts?
Choose a strategy based on data. Last write wins, using server timestamps, is simple but can lose edits. Field-level merging keeps non-conflicting changes. For lists, treat each item as a separate record with its own version so edits rarely clash. For collaborative content, CRDT-based approaches merge automatically. Always let the server decide final order, and show users when their change was overwritten.
08
After a release, crash reports show a spike only on one Android OS version. What steps do you take?
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.
09
What are optimistic updates and how do you implement them?
An optimistic update changes the UI immediately as if the server request succeeded, such as liking a post, then rolls back if the request fails. It makes apps feel fast on slow networks. With TanStack Query, use onMutate to update the cache and save the previous value, onError to restore it, and onSettled to refetch. Use it for low-risk actions, not payments.
10
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.
11
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.
12
Why use TanStack Query for server state in mobile apps?
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.
13
How do you handle gestures such as swipe to delete in React Native?
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.
Run the app in profile mode on a real device, not debug or emulator. Use Flutter DevTools: the performance view shows frame build and raster times, the CPU profiler finds expensive functions, and the memory view tracks allocations and leaks. Target under about 16 milliseconds per frame for 60 fps. The performance overlay shows UI and raster thread graphs, and rebuild tracking highlights widgets rebuilding too often.
15
What are useMemo, useCallback and React.memo used for?
React.memo skips re-rendering a component when its props are shallowly equal. useCallback keeps the same function reference between renders, and useMemo caches a computed value, both only changing when dependencies change. They help when passing callbacks to memoised list items or computing expensive values. Overusing them adds complexity with little gain; the React Compiler can now apply such memoisation automatically in supported projects.
16
A screen re-renders every time the user types in a search box, making it laggy. How do you fix it?
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.
17
After upgrading React Native, a third-party library breaks on the New Architecture. What do you do?
Check the library's documentation and the React Native directory for New Architecture support, and update to the latest version, since many libraries added support. The interop layer often lets old-architecture modules work, so read the error carefully. If unsupported, look for a maintained alternative, contribute a fix or patch with patch-package, or temporarily keep the old architecture only if your version still allows it, while planning a replacement.
18
How do you handle app-wide theming and dark mode in Flutter?
Define ThemeData for light and dark modes in MaterialApp, using ColorScheme.fromSeed to generate consistent Material 3 colours, and set themeMode from a settings state, saved in shared preferences. Widgets read Theme.of(context).colorScheme and textTheme instead of hardcoded colours. Add ThemeExtension classes for brand-specific tokens. This keeps the design consistent and makes switching themes a single state change.
19
After an API call finishes, the app throws an error about using BuildContext across async gaps or setState after dispose. How do you fix it?
The user left the screen before the Future completed, so the widget was unmounted. Before using context or calling setState after await, check if (!context.mounted) return; or if (!mounted) return; in State. Better still, move async logic out of widgets into a state management layer that the UI listens to, and cancel subscriptions or timers in dispose so no callbacks run on a dead widget.
20
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.
21
How do you manage form state and validation across multiple steps in a Flutter onboarding flow?
Keep the onboarding data in one state object owned by a notifier or cubit scoped to the flow, with each step updating its part. Validate per step before moving forward and again on final submit. Save progress locally so users can resume if they leave. Keep validation rules in pure functions that are unit tested. Dispose the state when the flow completes so data does not leak into later sessions.
22
Write an EAS configuration for development, preview and production builds.
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.
24
How do you think about mobile system design for a chat feature?
Start with requirements: one-to-one or group, media, read receipts, offline sending. The client keeps a local database as source of truth, shows sent messages instantly with a pending status, and syncs over a WebSocket while foregrounded, using push notifications in background. Handle reconnection, ordering by server timestamps, pagination of history, and retries with idempotent message IDs. Encrypt sensitive data and limit media size before upload.
25
What is a performance budget and how do you enforce it?
A performance budget sets limits on metrics like cold start time, app download size, frame rendering time and memory usage. Enforce it by measuring in CI, for example tracking release build size per pull request and running startup benchmarks on a reference device, and failing or flagging builds that exceed limits. Budgets make performance a shared responsibility rather than something fixed only after users complain.
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.
27
Users say the app does not work properly on foldable phones and tablets. What do you check?
Check whether orientation is locked, layouts use fixed widths, and screens assume phone dimensions. Make layouts adapt by width breakpoints with two-pane layouts on wide screens, handle configuration and size changes without losing state, and avoid hardcoding aspect ratios. Recent Android versions ignore orientation locks on large screens, so locking is no longer a fix. Test with resizable emulators, foldable postures and split-screen mode.
28
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.
29
How does the keyboard affect layouts in React Native and how do you handle it?
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.
30
A payment shows success in the app but the order is not created on the server. How would you fix the flow?
The app is probably treating the SDK's success callback as final and the verification call failed or was never sent, for example when the app was killed. Make the backend the source of truth: verify payments with the gateway's signature on the server and use webhooks to update orders even if the app never reports back. The app should poll order status after payment and show a pending state until confirmed.
Tips to crack the Dream11 Mobile App Development interview
Practise system design for sudden traffic spikes, such as many users joining just before a cricket match starts.
Prepare analytics cases on user engagement, retention and contest participation around major tournaments.
Keep up with regulatory changes affecting online gaming in India, as they directly shape the company's business.
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; Dream11 interviewers usually ask follow-ups on your first answer.
Frequently asked questions
How many rounds are there in the Dream11 Mobile App Development interview?
Candidates usually go through 5 stages: Online assessment or assignment; Technical round 1; Technical round 2 (design or case); Hiring manager round; Culture fit 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 Dream11 Mobile App Development interview?
This practice set leans on Testing, Performance and CI/CD (7), Mobile Backend, APIs and Firebase (5), Flutter State Management and Architecture (4), React Native Navigation, State and Native Modules (4). Revise those first, then practise explaining one or two of your own projects end to end, because most Dream11 interviewers ask you to walk through real work.
Are these the exact questions asked at Dream11?
No. These are curated practice questions that match the skills and difficulty usually tested in product interviews like Dream11's. They are not a leaked or verified list of past questions.
Where does Dream11 hire Mobile App Development professionals in India?
Dream11 has large teams in Mumbai. Openings and locations change often, so check the Dream11 careers page and filter by city and experience.
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