Curated interview practice questions with answers. These are practice scenarios, not a verified list of past interview questions.
About Wipro hiring for MEAN Stack roles
Wipro is an Indian multinational technology services and consulting company providing IT, cloud, cybersecurity, engineering and data analytics services to enterprises worldwide. Its delivery teams work on application development, quality engineering and data platforms for clients in sectors like banking, healthcare and energy. In India it hires for testing, data analysis, support and development roles through programmes such as Wipro Elite NTH.
For MEAN Stack roles, this Wipro practice set focuses most on RxJS, Signals and State Management (6), Node.js and Express APIs (5), Angular Components and Templates (4), Services, Dependency Injection and Routing (4). It has 15 easy, 14 medium, 1 hard questions, so you can start easy and work up to the harder ones.
Company type
IT services
Headquarters
Bengaluru, India
Main India offices
Bengaluru, Hyderabad, Pune, Chennai, Kolkata
Wipro MEAN Stack interview process
Online assessment (aptitude + written communication)
Coding test
Technical interview
HR round
Typical pattern based on public candidate experiences. Rounds vary by role, team and year.
Solved for WiproStart practicing
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01
What is an Angular component and what are its main parts?
A component controls a piece of the screen. It is a TypeScript class decorated with @Component, which provides a selector used as an HTML tag, a template or templateUrl for the view, styles or styleUrl for scoped CSS, and imports for other standalone components, directives and pipes it uses. The class holds data and event handlers, and the template binds to them.
02
How does lazy loading work with the Angular router?
Lazy loading defers downloading a feature's code until the user navigates to it. Use loadComponent: () => import('./admin/admin.component').then(m => m.AdminComponent) for a single component, or loadChildren to load a file of child routes. The CLI builds a separate chunk for each lazy route. You can add preloading strategies like withPreloading(PreloadAllModules) to fetch lazy chunks in the background after startup.
03
How do you test an Angular service that makes HTTP calls?
Provide provideHttpClient() and provideHttpClientTesting() in TestBed, then inject the service and HttpTestingController. Call the service method and subscribe, use httpMock.expectOne('/api/products') to capture the request, assert its method and body, and flush a fake response. Finally call httpMock.verify() to ensure no unexpected requests remain. This tests the service logic without a real backend.
04
How do you validate request data in an Express API, and why is it necessary even with Angular validation?
Frontend validation improves user experience, but anyone can call the API directly with tools like Postman or curl, so the server must validate everything. Use a schema library such as zod, Joi or express-validator in middleware to check types, required fields, lengths and formats, reject unknown fields and return 400 with clear field errors. Mongoose validation is a second layer close to the data.
05
What is the difference between signal, computed and effect?
signal() creates writable state. computed() derives a read-only value from other signals, is lazily evaluated and memoised, and recalculates only when its dependencies change, for example a cart total from cart items. effect() runs side effects whenever signals it reads change, such as logging or syncing to local storage. Use computed for derived data and keep effects for non-UI side effects, not for setting other state.
06
Write a standalone Angular component that displays a list of products using @for.
A Promise represents one future value, starts executing immediately when created and cannot be cancelled natively. An Observable can emit zero, one or many values over time, is lazy so nothing happens until you subscribe, and can be cancelled by unsubscribing. Observables also offer operators like map, filter, debounceTime and switchMap. Angular's HttpClient, router events and reactive forms all expose Observables.
08
Write a custom pure pipe that shortens long text with an ellipsis.
Use forkJoin to run all three requests in parallel and emit once when all complete, giving an object or array of results. Handle errors per request with catchError returning a fallback value, so one failed widget does not block the whole dashboard. If any source emits repeatedly, use combineLatest instead. With signals, you could use three httpResource instances and a computed for the combined loading state.
10
What is the difference between an interface and a type alias in TypeScript?
Both describe the shape of data. Interfaces are open, so declarations with the same name merge, and they can be extended with extends, which suits object models and class contracts. Type aliases can describe unions, intersections, tuples, primitives and mapped types, such as type Status = 'active' | 'blocked'. Many teams use interfaces for object shapes like API models and type aliases for unions and utility compositions.
11
How is routing configured in a standalone Angular application?
You define a Routes array mapping paths to components, with redirectTo, child routes and a wildcard ** route for 404 pages, and register it with provideRouter(routes) in app.config.ts. The root template contains <router-outlet />, links use routerLink and routerLinkActive, and code navigates with Router.navigate. Features such as withComponentInputBinding let route parameters bind directly to component inputs.
12
How do you explain database trade-offs, such as choosing MongoDB over SQL, to a client?
Situation: a client asked why we proposed MongoDB instead of the SQL database they knew. Task: explain clearly without jargon. Action: I mapped their product catalogue with varying attributes to documents, showed how it reduced joins and schema changes, admitted where SQL would be better, like complex financial reports, and proposed a reporting export. Result: the client approved MongoDB with confidence in the plan.
13
How do you read route parameters and query parameters in an Angular component?
Inject ActivatedRoute and read paramMap or queryParamMap, which are Observables, for example route.paramMap.pipe(map(p => p.get('id'))), so the component updates when the same route is reused with a new id. A snapshot gives a one-time value. With withComponentInputBinding enabled in provideRouter, route params, query params and resolver data can bind directly to component inputs, which is the simplest modern approach.
14
How do you design REST endpoints for a resource like orders, including nested data?
Use plural nouns and HTTP methods: GET /orders, GET /orders/:id, POST /orders, PATCH /orders/:id and DELETE /orders/:id. For related data, use shallow nesting like GET /users/:id/orders. Express actions that are not CRUD as sub-resources or clear verbs, such as POST /orders/:id/cancel. Support filtering, sorting and pagination with query parameters, return proper status codes and document the API with OpenAPI.
15
Write a cart service using signals with computed totals.
The user submits credentials from an Angular form to an Express login route. The server verifies the bcrypt password hash and signs a short-lived access token containing the user id and role, often with a refresh token in an httpOnly cookie. Angular stores the access token in memory, an interceptor attaches it to requests, Express middleware verifies it, and guards control which routes the user can open.
17
Write an Nginx server block that serves Angular and proxies /api to Node.
Since Angular 14, reactive forms are strongly typed. A FormControl<string> knows its value type, so form.value and getRawValue return typed objects and the compiler catches wrong field names. Controls are nullable by default because reset sets them to null; using nonNullable: true or NonNullableFormBuilder resets to the initial value instead. Typed forms make it safe to map form values directly to API request interfaces.
RxJS is a library for reactive programming with Observables, streams of values over time, combined using operators. Angular uses it in HttpClient, router events, reactive forms valueChanges and many third-party libraries. It excels at asynchronous workflows such as type-ahead search, polling, websocket streams, retries and combining multiple requests. Signals handle synchronous state well, while RxJS remains the tool for complex event streams.
20
Write a type-ahead search using a reactive FormControl and RxJS operators.
Prefer the async pipe in templates or toSignal, which subscribe and unsubscribe automatically. For manual subscriptions, use takeUntilDestroyed() from the rxjs-interop package, which completes the stream when the component's DestroyRef fires. HttpClient requests complete on their own, but long-lived streams like intervals, store selectors, router events and websockets must be cleaned up. Avoid nested subscribe calls; use flattening operators instead.
22
Configure an Angular dev server proxy to forward API calls to Express.
proxy.conf.json in the Angular project:
{
"/api": {
"target": "http://localhost:3000",
"secure": false,
"changeOrigin": true,
"logLevel": "debug"
}
}
angular.json, under serve options:
"proxyConfig": "proxy.conf.json"
Then call relative URLs in services, such as this.http.get('/api/products'), and run ng serve. The browser talks only to the dev server, so no CORS setup is needed locally.
23
Write a group validator that checks password and confirm password match.
Avoid heavy aggregation on every request. Precompute summaries with scheduled jobs or on write events and store them in a summary collection, cache the response in Redis with a short TTL, and return only the fields the dashboard needs. Use indexes for any live queries, add pagination for detail lists, and expose a separate endpoint for drill-down data so the first load stays fast.
26
What is a route resolver and when would you use one?
A resolver fetches data before a route activates, so the component receives ready data instead of showing an empty state first. A functional resolver, ResolveFn<Product>, uses inject() to call a service and returns an Observable or Promise. The data is available through ActivatedRoute or bound inputs. Use it for detail pages that are useless without data, but avoid it for slow calls, because navigation waits.
27
What are pipes in Angular and what is the difference between pure and impure pipes?
Pipes transform values in templates, such as {{ price | currency:'INR' }}, date, uppercase, json and async. A pure pipe, the default, runs only when its input reference or primitive value changes, so it is very efficient. An impure pipe runs on every change detection cycle, which can hurt performance, and is needed only when output depends on mutable data. Prefer pure pipes or computed signals.
28
How do you serve an Angular build and an Express API from the same Node server?
Build Angular with ng build, which outputs static files to dist/project/browser. In Express, register API routes under /api first, then serve the static files with express.static, and finally add a catch-all GET route that returns index.html so Angular routing works on refresh. In larger deployments, Nginx or a CDN usually serves the Angular files while Express handles only the API.
29
How do built-in and custom validators work in reactive forms?
Validators are functions that take a control and return null when valid or an error object like { required: true } when invalid. Built-ins include Validators.required, email, minLength, maxLength, pattern, min and max. A custom validator follows the same ValidatorFn signature, for example rejecting weak passwords. Group-level validators can compare fields, such as password and confirm password. Errors are read through control.errors and control.hasError.
30
Walk me through the MEAN project you are most proud of.
Situation: for my final-year project I built a hospital appointment system. Task: let patients book slots and doctors manage schedules. Action: I designed MongoDB collections with indexes for slots, built a TypeScript Express API with JWT and role checks, and an Angular frontend with reactive forms, guards and signals. I added tests and deployed with Docker on a cloud VM. Result: our college clinic used it for a semester.
Tips to crack the Wipro MEAN Stack interview
Prepare for the essay writing section in the online test by practising short, clear, grammatically correct essays on general topics.
Revise basic coding problems on strings and arrays plus fundamentals of DBMS, operating systems and computer networks.
Learn about Wipro's values, known as the Spirit of Wipro, and its focus areas such as cloud and cybersecurity.
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; Wipro interviewers usually ask follow-ups on your first answer.
Frequently asked questions
How many rounds are there in the Wipro MEAN Stack interview?
Candidates usually go through 4 stages: Online assessment (aptitude + written communication); Coding test; Technical interview; HR 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 Wipro MEAN Stack interview?
This practice set leans on RxJS, Signals and State Management (6), Node.js and Express APIs (5), Angular Components and Templates (4), Services, Dependency Injection and Routing (4). Revise those first, then practise explaining one or two of your own projects end to end, because most Wipro interviewers ask you to walk through real work.
Are these the exact questions asked at Wipro?
No. These are curated practice questions that match the skills and difficulty usually tested in it services interviews like Wipro's. They are not a leaked or verified list of past questions.
Where does Wipro hire MEAN Stack professionals in India?
Wipro has large teams in Bengaluru, Hyderabad, Pune, Chennai, Kolkata. Openings and locations change often, so check the Wipro careers page and filter by city and experience.