Expert · Capstone, portfolio and getting work · topic 33 of 34 · 30 min
Full-stack interviews in India
Explanation
The usual rounds
Every company is different, but most full-stack hiring in India uses some of these rounds. Ask the recruiter which ones you will face, then prepare for each.
| Round | What happens | How to prepare |
|---|---|---|
| Online assessment (OA) | A timed online test: aptitude questions and 1 to 3 coding problems | Practise timed problems; read each question twice before coding |
| DSA | Data Structures and Algorithms: arrays, strings, hash maps, sorting, sometimes trees and graphs, solved while you think aloud | Explain your idea first, then code, then test with small examples |
| Machine coding | Build a small working feature in 60 to 90 minutes, such as a to-do list with filters, a search box with suggestions or pagination | Get a simple version working end to end first, then improve it |
| Design (low-level or system design lite) | Design the tables and API for a small app, such as a URL shortener or the Notes app | Requirements first, then tables, then endpoints, then what changes with more users |
| Project deep dive | Many questions about a project on your resume | Know every decision and trade-off in your capstone |
| HR or managerial | Teamwork, a conflict, why this company, notice period and salary expectations | Prepare STAR stories and be honest |
Service companies, product companies and startups
- Service companies build software for client businesses. They often hire freshers in large batches: an online test, a technical interview on basics and your projects, then HR. Strong fundamentals and clear communication matter most.
- Product companies build and sell their own software. They usually have harder DSA rounds, a machine coding or design round, and deeper follow-up questions.
- Startups are small, young companies. They often give a take-home task or a practical round, care a lot about what you have shipped, and may ask you to work on frontend, backend and deployment from the first week.
- These are general patterns, not rules. Read the job post carefully and ask the recruiter what the rounds are.
Common technical questions
| Question | What a good answer covers |
|---|---|
| What happens when you type a URL and press Enter? | DNS finds the server's IP address; the browser opens a connection and does the TLS (HTTPS) handshake; it sends an HTTP request; the server runs code and may query the database; the response comes back; the browser reads the HTML, loads CSS and JavaScript and paints the page. |
| Explain REST status codes | 200 OK, 201 Created, 204 No Content, 400 bad input, 401 not logged in, 403 logged in but not allowed, 404 not found, 409 conflict, 500 server error. |
| SQL joins and indexes | INNER JOIN keeps only rows that match in both tables; LEFT JOIN keeps every row of the left table. An index is a sorted lookup that makes WHERE and ORDER BY fast, but makes writes a little slower. |
| Sessions vs JWT | A session keeps state on the server and the cookie holds only a random id, so logout works at once. A JWT is a signed token that carries the data, so the server stores less, but cancelling it before it expires is harder. |
| What is CORS? | A browser rule: a page from one origin can read a response from another origin only if that server allows it with Access-Control-Allow-Origin headers. It protects users; it does not replace checks on the server. |
| When does a React component re-render? | When its state changes, when its parent re-renders, or when a context it uses changes. Never change state directly; call the setter with a new value. |
| How did you deploy your project? | Where it runs, how environment variables are set, how HTTPS works, how CI runs the tests, and what you would change for more users. |
// Machine coding classic: run the search only after the user stops typing
function debounce(fn, ms) {
let timer;
return (...args) => {
clearTimeout(timer);
timer = setTimeout(() => fn(...args), ms);
};
}
const search = debounce((q) => console.log('searching for', q), 300);
search('pu'); search('pun'); search('pune'); // only 'pune' is searchedExplaining your own project
Prepare a 2-minute story of your capstone: the problem, who used it, the stack and why, one hard bug and how you found it, one trade-off, and what you would do next. Interviewers will then dig into any part, so re-read your own code the day before.
STAR answers
Behavioural questions ask how you acted in the past, such as "Tell me about a time you missed a deadline". STAR is a simple shape for the answer: Situation (the background in one line), Task (what you had to do), Action (what you did, in detail, saying "I", not "we") and Result (what happened, with a number if you have one, and what you learned).
Situation: Two days before our college fest, the booking app I built showed some events as full when seats were free.
Task: Fix it before bookings opened at 9 am.
Action: I reproduced the bug with a test, found that cancelled bookings were still counted, changed the query to count only confirmed bookings, and added the test to CI.
Result: Bookings opened on time and about 300 students booked with no seat errors. I now write a test for every bug I fix.Ask good questions at the end
- What would I work on in my first three months?
- How is code reviewed and deployed here?
- Is there a mentor or buddy for new joiners?
- What does a good first year look like in this role?
Watch the lesson
Full-stack interviews in India · 1/7
Full-stack interviews in India usually mix a few rounds. Let us see each one.
Prefer a video by a teacher? Find free videos on “full stack developer interview preparation machine coding round india” on YouTube ↗
In real life: A machine coding round for a junior role
A candidate gets 90 minutes to build a product list with a search box and pagination, using a given JSON file. She first shows the list on screen (15 minutes), then adds search (20 minutes), then pagination with Previous and Next buttons (25 minutes), then edge cases: no results, the last page and an empty search. She talks through each step. Another candidate spends an hour on styling and ends with pagination that breaks on the last page. The first candidate goes to the next round: a simple version that works and clear thinking beat a pretty screen that fails.
Practice (0/3 done)
A machine coding favourite. Write paginate(items, page, size) that returns { page, totalPages, items } (keys in this order). totalPages is Math.ceil(items.length / size) but never less than 1. If page is below 1, use 1; if it is above totalPages, use totalPages. items holds that page's slice (page 1 is the first size items). Do not change the input array.
Another common machine coding task. Write groupBy(items, keyFn) that returns an object: each key is keyFn(item), and its value is the array of items with that key, in their original order. Keys must appear in the order they are first seen. Write it with a loop yourself (interviewers often ask you not to use Object.groupBy).
Do a 60-minute mock interview with a friend (take turns as interviewer) or record yourself. Follow the plan in the checklist, then write down three things to improve.
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