.NET Full Stack Interview Questions in Visakhapatnam
36 practice questions with answers for .NET Full Stack interviews in Visakhapatnam.
.NET Full Stack jobs in Visakhapatnam
Visakhapatnam (Vizag) has a developing IT market with delivery centres, start-ups and IT parks around Rushikonda. Many local candidates also apply to Hyderabad and remote roles, so a mix of service and product styles is common.
Below are 36 questions that match the mix of service, product and domain employers hiring .net developers in Visakhapatnam.
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01
Angular or React with ASP.NET Core: how do you choose?
Angular is a complete framework with routing, forms, HTTP, dependency injection and TypeScript built in, which suits large enterprise apps and teams that want strong conventions. React is a UI library with a large ecosystem, giving more freedom to pick routing and state tools, and is popular in product startups. Both work equally well with an ASP.NET Core API. Choose based on team skills, project size and the company's existing stack.
Func<decimal, decimal> addGst = price => price * 1.18m;
Action<string> log = msg => Console.WriteLine($"[LOG] {msg}");
Predicate<int> isAdult = age => age >= 18;
decimal total = addGst(1000m); // 1180
log($"Total {total}");
bool ok = isAdult(21); // true
Func returns a value (last type argument is the return type), Action returns void, and Predicate<T> returns bool. They save you from declaring custom delegate types.
03
Show the useState and useEffect hooks in a React component.
import { useState, useEffect } from 'react';
export function Timer() {
const [seconds, setSeconds] = useState(0);
useEffect(() => {
const id = setInterval(() => setSeconds(s => s + 1), 1000);
return () => clearInterval(id); // cleanup on unmount
}, []); // empty array: run once
return <p>Elapsed: {seconds}s</p>;
}
useState stores state that triggers re-render; useEffect runs side effects after render, and its dependency array controls when it re-runs.
04
What is the difference between const, readonly and static readonly?
const is a compile-time constant, implicitly static, and its value is copied into calling assemblies, so changing it requires recompiling them. readonly fields are set at declaration or in the constructor and can differ per instance. static readonly is set once per type at runtime, so it can hold values like DateTime.Now or a new object. Use const only for values that will never change, such as Math.PI.
05
Write a SQL Server query to find the second highest salary.
-- using DENSE_RANK (handles ties)
SELECT Salary
FROM (
SELECT Salary, DENSE_RANK() OVER (ORDER BY Salary DESC) AS rnk
FROM Employees
) t
WHERE rnk = 2;
-- using OFFSET
SELECT DISTINCT Salary
FROM Employees
ORDER BY Salary DESC
OFFSET 1 ROW FETCH NEXT 1 ROW ONLY;
Change 2 to N for the Nth highest salary.
06
Protect an Angular route so only logged-in users can open it.
async marks a method that can contain await, and the compiler turns it into a state machine. await pauses the method until a Task finishes without blocking the thread; the thread returns to the pool to do other work and the method resumes later, often on another thread. It is ideal for I/O such as database calls, HTTP requests and file reads. An async method returns Task, Task<T> or ValueTask.
08
A job matches 2 lakh uploaded records against 2 lakh existing IDs using list.Where(x => existingIds.Contains(x.Id)) and takes minutes. What is wrong?
existingIds is a List, so Contains is O(n) and the whole operation becomes O(n x m), around 40 billion comparisons. Convert the IDs to a HashSet<int> first, making each lookup O(1) and the job run in milliseconds. If you also need associated data, build a Dictionary keyed by ID. Always check data structure complexity before parallelising or adding hardware.
09
What are useMemo and useCallback used for in React?
useMemo caches the result of an expensive calculation and recalculates only when its dependencies change, such as filtering 10,000 rows. useCallback caches a function reference so that a child wrapped in React.memo does not re-render just because a new function was created. Both are optimisations and add complexity, so use them where profiling shows a problem. The React Compiler, stable since late 2025, can apply much of this memoisation automatically.
A delegate is a type-safe reference to a method with a specific signature, similar to a function pointer but checked by the compiler. You can pass methods as parameters, store them and call them later. Delegates can be multicast, holding several methods that run in order. Lambdas, LINQ, events and callbacks are all built on delegates, and the built-in Func and Action types cover most needs.
11
Show bulk update and delete with ExecuteUpdate and ExecuteDelete.
// mark all unpaid invoices older than 30 days as overdue
int updated = await db.Invoices
.Where(i => !i.IsPaid && i.DueDate < DateTime.UtcNow.AddDays(-30))
.ExecuteUpdateAsync(s => s
.SetProperty(i => i.Status, "Overdue")
.SetProperty(i => i.UpdatedAt, DateTime.UtcNow));
// delete old logs
int deleted = await db.AuditLogs
.Where(l => l.CreatedAt < cutoff)
.ExecuteDeleteAsync();
These run a single SQL UPDATE or DELETE without loading entities, available since EF Core 7. They bypass the change tracker.
12
Tell me about a time you refactored messy code that others depended on.
In my last project (Situation) an invoice module had one 900-line class with duplicated GST logic. My task was to add a new tax rule without breaking billing. I first wrote unit tests around current behaviour, then extracted tax rules into strategy classes and moved data access into a repository, merging in small pull requests. Result: the new rule took one day, and bugs in that module dropped noticeably the next quarter.
An event is a delegate wrapped with restricted access. Outside the class, subscribers can only add or remove handlers with += and -=; they cannot invoke the event or overwrite the whole list with =. This protects the publisher. The standard pattern uses EventHandler<TEventArgs> with sender and args. Remember to unsubscribe long-lived subscriptions, otherwise the publisher keeps subscribers alive and causes memory leaks.
14
Which HTTP status codes and methods should a REST API use, and what is the difference between PUT and PATCH?
GET reads, POST creates, PUT replaces, PATCH partially updates and DELETE removes. Return 200 OK for success with a body, 201 Created with a Location header after POST, 204 No Content after delete, 400 for invalid input, 401 unauthenticated, 403 forbidden, 404 not found, 409 conflict and 500 for server errors. PUT sends the full resource and is idempotent; PATCH sends only changed fields.
15
What are components and standalone components in Angular?
A component is a TypeScript class with the @Component decorator, a template and styles, representing one piece of UI such as a product card. Earlier, every component had to be declared in an NgModule. Standalone components import their own dependencies directly through the imports array and need no module; since Angular 19 they are the default. This simplifies apps, enables easier lazy loading and is the recommended approach in 2026.
16
Show the difference between ROW_NUMBER, RANK and DENSE_RANK with a query.
SELECT Name, Department, Salary,
ROW_NUMBER() OVER (PARTITION BY Department ORDER BY Salary DESC) AS RowNum,
RANK() OVER (PARTITION BY Department ORDER BY Salary DESC) AS Rnk,
DENSE_RANK() OVER (PARTITION BY Department ORDER BY Salary DESC) AS DenseRnk
FROM Employees;
-- salaries 90, 90, 80 give
-- ROW_NUMBER: 1, 2, 3
-- RANK: 1, 1, 3
-- DENSE_RANK: 1, 1, 2
PARTITION BY restarts numbering for each department.
public sealed class AppConfig
{
private static readonly Lazy<AppConfig> _instance =
new(() => new AppConfig());
public static AppConfig Instance => _instance.Value;
private AppConfig()
{
// load settings once
}
}
Lazy<T> is thread-safe by default and creates the object only on first access. The private constructor and sealed class prevent other instances. In ASP.NET Core, prefer AddSingleton.
18
What is the difference between == and Equals() in C#?
For reference types, == by default checks reference equality, meaning both variables point to the same object, while Equals can be overridden to compare content. String overrides both, so == compares text. For value types, Equals compares field values. Records generate value-based equality automatically. When you override Equals, also override GetHashCode so objects behave correctly in dictionaries and hash sets.
19
What are your strengths and weaknesses as a developer?
My strength is that I go deep when debugging; I like reading execution plans and logs until I find the real cause, which has helped my team fix slow queries. A weakness was that I spent too long polishing code before asking for feedback. I now open small draft pull requests early and ask for review, which has made me faster and helped me learn from seniors sooner.
20
Show a class using a primary constructor with dependency injection.
public class OrderService(IOrderRepository repo, ILogger<OrderService> logger)
{
public async Task<Order?> GetAsync(int id)
{
logger.LogInformation("Fetching order {Id}", id);
return await repo.FindAsync(id);
}
}
Primary constructors on classes arrived in C# 12. Parameters are captured and usable in all members, removing boilerplate fields. They are not readonly, so assign to a readonly field if immutability matters.
21
An admin page renders 20,000 rows in a table and the browser freezes. How do you fix it?
Do not send or render everything at once. Add server-side paging, sorting and filtering in the ASP.NET Core API so the page loads perhaps 50 rows at a time. If users truly need to scroll a long list, use virtual scrolling, such as Angular CDK virtual scroll or TanStack Virtual in React, so only visible rows exist in the DOM. Also use trackBy or keys, and debounce search inputs.
22
What is the difference between JIT compilation and Native AOT in .NET?
With JIT, the app ships as IL and the runtime compiles methods to machine code when first called; tiered compilation later recompiles hot methods with better optimisation. Native AOT compiles everything ahead of time into a single native executable, giving very fast startup and lower memory, which suits containers and serverless. The trade-off is limited reflection and dynamic code generation, so some libraries need source generators to work.
23
Fetch products from an ASP.NET Core API in React with loading and error states.
// split 1,000 ids into batches of 100 for bulk API calls
foreach (int[] batch in ids.Chunk(100))
await SendBatchAsync(batch);
// unique customers by email
var unique = customers.DistinctBy(c => c.Email).ToList();
// highest-paid employee object, not just the salary
Employee? top = employees.MaxBy(e => e.Salary);
These were added in .NET 6 and remove the need for custom helpers or third-party libraries like MoreLINQ.
In five years I want to be a senior full stack engineer who can design a complete .NET system, from database and APIs to front end and cloud deployment, and guide newer developers. In the near term I want to master ASP.NET Core, EF Core and SQL Server performance, then grow into Azure and system design. I would like to grow inside one company where I can take on bigger modules over time.
26
What is the difference between controllers and Minimal APIs?
Controllers group actions into classes with attributes for routing, filters and model binding, which suits large APIs with many conventions. Minimal APIs map endpoints directly with app.MapGet and lambdas, with less ceremony and slightly better performance, ideal for microservices and small APIs. Since .NET 7 they support filters, route groups and OpenAPI, and .NET 10 adds built-in validation, so both are production-ready choices.
27
Several threads update an in-memory Dictionary cache in a singleton service and you see corrupted data and exceptions. What would you use instead?
System.Collections.Concurrent provides thread-safe collections: ConcurrentDictionary, ConcurrentQueue, ConcurrentStack, ConcurrentBag and BlockingCollection. They use fine-grained locking or lock-free techniques, so multiple threads can read and write without your own lock. Use ConcurrentDictionary for in-memory caches in singleton services. Note that GetOrAdd may run the value factory more than once under contention, so keep the factory side-effect free or wrap it in Lazy<T>.
I can contribute on both sides of a feature: I have built ASP.NET Core APIs with EF Core and SQL Server, and front ends in Angular and React, and deployed them myself. I write clean, tested code and I am comfortable reading logs and execution plans when things break. I learn quickly, ask questions early and take ownership, so you can give me a module and trust that it will be completed properly.
virtual marks a base method as replaceable. override in a derived class replaces it, so calls through a base reference run the derived version. new hides the base method instead: a call through a base reference still runs the base version, and only a derived-type reference sees the new one. Method hiding is usually a sign of a design problem, and the compiler warns when you hide without writing new.
31
How would you deploy an Angular or React front end together with an ASP.NET Core API?
Two common options exist. Build the SPA with ng build or npm run build and serve the static files from the API's wwwroot with UseStaticFiles and MapFallbackToFile, giving one deployment and no CORS. Or host the SPA separately on a CDN or static hosting such as Azure Static Web Apps and the API on App Service or containers, which scales independently. Use environment config for API URLs and a CI/CD pipeline for both.
32
A developer runs two EF Core queries in parallel with Task.WhenAll on the same DbContext and gets an InvalidOperationException. Why?
DbContext is not thread-safe and supports only one active operation at a time, so starting a second query before the first finishes throws 'A second operation was started on this context instance'. Either await the queries one after another, or create a separate context for each parallel query using IDbContextFactory. Usually sequential queries are fine; parallelism only helps when the queries are slow and independent.
33
Give an example of a Liskov Substitution Principle violation and how to fix it.
A classic case is Square inheriting Rectangle. Setting Width on a square also changes Height, so code that sets width 5 and height 4 and expects area 20 breaks. Another real case is a ReadOnlyRepository that inherits Repository and throws NotSupportedException on Save. The fix is to model shared behaviour with interfaces such as IShape or IReadRepository and IWriteRepository, so subclasses never weaken the contract.
34
Using LINQ, group employees by department and get the count and average salary.
var report = employees
.GroupBy(e => e.Department)
.Select(g => new
{
Department = g.Key,
Count = g.Count(),
AvgSalary = g.Average(e => e.Salary)
})
.OrderByDescending(x => x.AvgSalary)
.ToList();
GroupBy returns groups with a Key, and aggregate methods run per group. With EF Core this translates to SQL GROUP BY.
35
Write a recursive CTE that lists an employee hierarchy with levels.
WITH Org AS (
SELECT Id, Name, ManagerId, 0 AS Lvl
FROM Employees
WHERE ManagerId IS NULL -- anchor: CEO
UNION ALL
SELECT e.Id, e.Name, e.ManagerId, o.Lvl + 1
FROM Employees e
JOIN Org o ON e.ManagerId = o.Id -- recursive part
)
SELECT REPLICATE(' ', Lvl) + Name AS Hierarchy, Lvl
FROM Org
OPTION (MAXRECURSION 100);
The anchor query runs once and the recursive part repeats until no new rows are found.
36
A read-only product listing endpoint in EF Core uses a lot of memory and CPU. What simple change helps, and why?
By default, EF Core tracks every entity it loads so it can detect changes on SaveChanges, which costs memory and CPU. AsNoTracking tells EF Core not to track the results, making read-only queries faster and lighter. Use it for lists, reports and GET endpoints where you will not update the data. AsNoTrackingWithIdentityResolution avoids duplicate instances of the same entity in results while still skipping tracking.
Few big employers listed in Visakhapatnam?
Many Visakhapatnam candidates also apply to teams in Hyderabad and to remote or hybrid roles. Practise the Hyderabad set as well.
Which companies hire .NET Full Stack professionals in Visakhapatnam?
Companies with large offices in Visakhapatnam include many IT services and product firms. Use their company pages below to practise employer-specific sets.
Are .NET Full Stack interviews in Visakhapatnam different from other cities?
The questions depend more on the company than the city. Visakhapatnam's mix of employers decides the style: Many local candidates also apply to Hyderabad and remote roles, so a mix of service and product styles is common
How do I find .NET Full Stack jobs in Visakhapatnam?
Shortlist companies with Visakhapatnam offices, keep your CV focused on .NET Full Stack projects, apply on company career pages and job portals with the Visakhapatnam filter, and practise the questions on this page before each interview.