Full-stack mock interviews
A full-stack round is usually one feature followed all the way through rather than two shorter interviews stapled together. The question is whether you can hold both ends in your head at once and stay specific at each layer.
Rounds with Sia from ₹49 · Live interviews with a working engineer from ₹500 · Pay per session
What a Full-stack round covers
One feature, end to end
A single flow traced from the interaction to the request, the query and back to the render. The follow-ups tend to sit at the boundaries between layers, because that is where the vague answers live.
Where logic belongs
What to validate on the client, what to enforce on the server, and why duplicating a rule is sometimes right. Expect to justify the split rather than state it.
Contracts between layers
The shape of the payload, how errors surface to the user, and what happens when the two sides disagree about a field. Real answers usually come from having been burned once.
Trade-offs under time pressure
What you would ship first and what you would knowingly defer. Being able to name the shortcut is worth more than pretending you would not take one.
Full-stack interview questions you might be asked
Not a list to memorise. Each is the kind of opening a real round uses, with what a strong answer covers — the follow-ups depend on what you say.
A user clicks "Save" on their profile. Take me from the click to the database and back.
Every layer in order — the request, validation, the write, the response and what the screen shows — staying concrete at each boundary.
The client already validates the email field. Why validate it again on the server?
Because the client can be bypassed. A strong answer separates checks that help the user from rules that protect the data.
The API renamed a field and the app broke in production. How would you have prevented it?
Versioning or additive changes, a shared contract between both sides, and how a deploy order can make a safe change unsafe.
You have one week to ship a comments feature. What do you build first, and what do you leave out?
A clear first slice, the shortcut you are knowingly taking, and what would have to be true before you paid it back.
A page loads slowly. Is it the frontend or the backend?
How you would find out — the network tab, server timings, payload size — before naming a fix on either side.
Answer questions like these in a scored round and see exactly where your answer fell short.
What the interviewer is listening for
Breadth is assumed; the differentiator is whether you stay concrete when you cross a boundary. Answers that get vaguer the moment the question moves from the client to the database are the most common way this round is lost.
Where candidates lose marks
- Being sharp on one side and hand-waving the other.
- Describing an architecture without ever naming a trade-off.
- Skipping validation questions because "the frontend already checks it".
Two ways to interview
A round with Sia, on your own
One question at a time with real follow-ups on what you actually said. Choose three, five or eight questions. Scored the moment you finish, with a written breakdown across technical depth, problem solving and communication.
A live interview with an engineer
Forty minutes over Zoom with someone who runs full-stack interviews for a living. They score five criteria and write up what to fix, and you keep a numbered certificate for the session.
Pick your stack for a round with Sia: React · Node.js · JavaScript · Python · Java · Rails.
Questions about full-stack interviews
Is a full-stack round just a frontend round plus a backend round?
No. It usually follows one feature through every layer, and the follow-ups sit at the boundaries between them, which is where vague answers show.
Which stacks can I pick?
React, Node.js, JavaScript, Python, Java or Rails for a round with Sia. Pick the stack you are actually applying with.
Is a full-stack round right for a fresher?
Yes. Many freshers have built one full-stack project, and walking through it end to end is exactly the kind of answer this round rewards. Choose Beginner difficulty to start.
How is a full-stack round scored?
On the same five criteria as every round, so you can compare it with your frontend or backend scores and see which side needs the work.
Read before your round
Full-stack interviews by technology
Other tracks
Not sure which to book? The FAQ covers how sessions are scored, and candidate stories show what people did with the feedback.