I Built a Free Interview Prep Site : Here's What I Learned About What Interviewers Actually Ask

Ojas Sharma — Tue, 28 Jul 2026 16:39:19 +0000

I spent months going through tech interview prep — and the biggest thing I noticed is that most resources overcomplicate it.

You don't need to solve 500 LeetCode problems. You need to understand why the interviewer is asking what they're asking.

The Pattern I Noticed
After going through dozens of interviews (and failing a few), I realized most technical questions fall into a few buckets:

"Do you actually understand this, or did you memorize it?"

Questions like "Explain the 4 pillars of OOP" aren't trivia. The interviewer wants to hear you explain it like you'd explain it to a junior dev. If you sound like a textbook, you fail.

"Can you compare two things and pick the right one?"

"Array vs linked list — when would you use each?" isn't about reciting Big O. It's about showing you've made that decision in real code. Talk about cache locality, talk about insertion patterns in your actual projects.

"Do you know what you don't know?"

"What happens when you call new in C++?" — if you don't know about the free store, say so and talk about what you do know. Interviewers respect honesty over BS.

What I Built
I got tired of interview sites that either:

Give you a one-liner answer (useless)
Give you a 3000-word essay (nobody reads that before an interview)
So I built InterviewPrepNotes — free, no login, no paywall. Each question gets its own page with:

A clear answer in plain language
Code examples in multiple languages
What the interviewer is actually listening for
The follow-up questions to expect
It covers OOP, DSA, Java, C++, SQL, Spring Boot, API Design, and Cloud — basically everything that comes up in backend/fullstack interviews.

There's also a SQL Playground where you can practice queries right in the browser (runs SQLite via WebAssembly, no server needed).

A Few Questions Most People Get Wrong
Here are three that trip up even experienced devs:

"What's the difference between abstraction and encapsulation?"
Most people say "abstraction hides complexity, encapsulation hides data." That's technically right but it sounds memorized. The better answer: encapsulation is a mechanism (private fields, public methods). Abstraction is a design decision (what interface do I expose?). One is how you build the wall, the other is deciding where the wall goes.

"Stack vs Queue — when would you use each?"
Don't just say LIFO vs FIFO. Say: "I'd use a stack for undo functionality or parsing nested expressions. I'd use a queue for task scheduling or BFS." Concrete use cases > definitions.

"What's the difference between == and .equals() in Java?"
The trap: most people know == compares references. The follow-up they don't expect: "So what does == do with Integer values between -128 and 127?" (Java caches them, so == returns true — which breaks your mental model.)

The Honest Truth About Interview Prep
You don't need to mass-grind. Pick the 20-30 questions most likely to come up for your target role, and understand them deeply enough to explain them without notes. That beats 200 shallow answers every time.

If it helps anyone, the whole thing is free: interviewprepnotes.com

Happy to answer questions about the tech stack too — it's a static site on Vercel with zero backend, which was a deliberate choice to keep it fast and free forever.

DEV Community: Ojas Sharma

I Built a Free Interview Prep Site : Here's What I Learned About What Interviewers Actually Ask