AI Mock Interviews for DSA, System Design & LLD

Prepare for technical interviews at top companies like Google, Amazon, Meta, Microsoft, and Netflix with InstaMock's AI-powered mock interview platform. Practice system design (HLD), low-level design (LLD), data structures & algorithms (DSA), and behavioral interviews with our advanced AI interviewer. Get instant feedback, scoring, and improvement recommendations to master any technical round.

InstaMock offers four types of mock interviews to prepare comprehensively: 1) High Level Design (HLD) - system architecture and scalability for distributed systems; 2) Low Level Design (LLD) - object-oriented design and code architecture; 3) DSA - 200+ data structure and algorithm problems with AI evaluation; 4) Behavioral - leadership principles and situational interview questions.

Whether you're targeting SDE1 roles or aiming for senior engineer positions, our adaptive learning system helps you identify weak areas and track progress with detailed performance metrics. Book live 1:1 mock interviews with experienced engineers from Google, Amazon, Meta, Microsoft, and Netflix for personalized feedback and company-specific interview insights.

AI-Powered Mock Interviews

AI Mock Interviews forDSA & System Design

Practice AI-powered mock interviews for DSA, System Design (HLD), LLD, and 1:1 expert interviews. Get real-time feedback, detailed reports, and prepare for FAANG companies.

DSA Practice

200+ Problems

Solve coding problems with AI-powered evaluation and detailed feedback

ArraysTreesGraphsDP
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HLD Mock Interview

21 Questions

System design interviews with AI interviewer - Design WhatsApp, Netflix, Uber

ScalabilityMicroservicesDatabases
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LLD Coding

15+ Problems

Object-oriented design problems with SOLID principles evaluation

Design PatternsSOLIDOOP
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Mock Interview

Live Experts

Get interviewed by industry experts from top companies with real feedback

1:1 InterviewExpert PanelGoogle Meet
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Structured Placement Preparation

5-month live cohorts designed to take you from beginner to placement-ready.

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1:1 with a real interviewer

Book a session with a working engineer

Pay once, tell us when suits you, and we assign an interviewer. Sessions run 7–11pm IST on weekdays and 9am–11pm IST at weekends.

Guidance Session

Fifteen minutes with someone who has sat on the other side of the table

₹149one-off

15 minutes

This is a consultation, not a mock interview. You will not be interviewed or scored.

  • Short consultation with an assigned mentor or interviewer
  • Talk through your interview preparation strategy
  • Ask the HLD, LLD, DSA and technical questions you keep getting stuck on
  • Work out what to prioritise and where you are weakest
  • Leave with actionable next steps

One Mock Interview

A full round with an engineer who has taken hiring decisions

₹499one-off

60 minutes

A complete interview: you are asked, pushed back on, and scored.

  • One complete live mock interview with an assigned interviewer
  • Tailored to your CV, your experience and the round you pick
  • Structured evaluation and actionable feedback
  • Scheduled Google Meet session
  • Confirmation email and reminders
  • Booking dashboard with your session details
Best Value

Two Mock Interviews

Two rounds, so the second one shows whether the feedback landed

₹899total

₹449.50 per interview — saves ₹99 against two separate bookings

Two complete interviews, scheduled and tracked separately.

  • Two complete mock interview sessions
  • Practise different topics or different rounds
  • Feedback after each session
  • Time to improve between the two
  • Separate scheduling and status tracking for both interviews
  • Google Meet link and email notifications for each confirmed session

AI mock interviews stay free and unlimited. Try one now

Learn & Prepare

Learn System Design & LLD Concepts

Comprehensive guides and theory to master system architecture, design patterns, and algorithms

System Design Guides

13 Guides

Complete architecture guides for designing large-scale distributed systems

WhatsAppNetflixUberAmazonYouTube
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Learn LLD Concepts

5 Topics

Complete learning path: OOP, SOLID, Design Patterns, Concurrency & more

OOPSOLIDDesign PatternsConcurrency
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Coming Soon

DSA Learning Path

Coming Soon

Topic-wise DSA concepts with examples and practice problems

ArraysRecursionTreesDynamic Programming

Why Choose InstaMock?

Everything you need to ace your next interview

AI-Powered Interviews

Experience realistic interviews with intelligent AI that adapts to your responses and provides human-like feedback

Real-Time Scoring

Live feedback on multiple criteria including problem-solving, communication & technical depth

Multiple Interview Types

Practice system design, coding, behavioral & technical rounds - all in one platform

Instant Evaluation

Get detailed analysis of your performance with actionable improvement suggestions

45-Min Sessions

Full-length mock interviews that simulate real interview conditions

Interactive Chat

Have natural conversations with AI - ask questions, clarify requirements

Mock Interview Preparation Platform

Practice mock interviews with expert interviewers from top tech companies. Get real-time feedback, detailed performance reports, and actionable insights to crack your next interview.

1:1 Mock Interview with Industry Experts

Get interviewed by experienced engineers from Google, Amazon, Microsoft, Meta, and other top companies. Our mock interview sessions simulate real interview conditions, covering system design, data structures & algorithms, and behavioral rounds. Each session includes detailed feedback on your communication, problem-solving approach, and technical depth.

AI-Powered Mock Interview Practice

Practice unlimited mock interviews with our AI interviewer anytime, anywhere. Our AI evaluates your system design solutions, reviews your code in real-time, and provides instant feedback. Perfect for daily mock interview practice before your actual interview rounds at FAANG and top tech companies.

System Design Mock Interview

Master system design interviews with our comprehensive mock interview platform. Practice designing real-world systems like WhatsApp, Netflix, Uber, and YouTube. Learn high-level design (HLD) and low-level design (LLD) concepts through interactive mock interview sessions with step-by-step guidance and architecture feedback.

DSA Coding Mock Interview

Prepare for coding interviews with 200+ DSA problems and mock interview simulations. Practice arrays, trees, graphs, dynamic programming, and more in a real mock interview environment. Get AI-powered code review, time complexity analysis, and optimization suggestions to improve your problem-solving skills.

Why Mock Interviews Matter

Candidates who practice mock interviews are 3x more likely to receive job offers. Regular mock interview practice helps you overcome interview anxiety, improve your communication skills, structure your problem-solving approach, and build confidence. Whether you are preparing for your first mock interview or your tenth, InstaMock provides the tools and expert guidance you need to succeed in technical interviews at any company.

Ready to Ace Your Interview?

Join 5,000+ professionals preparing for their dream jobs with InstaMock

Choose your mock interview path:

System Design Mock InterviewLLD Mock InterviewDSA Mock Interview1:1 Expert Mock Interview
Frequently Asked Questions

Everything You Need to Know

Get answers to common questions about mock interviews, system design, DSA, and interview preparation

Mock Interviews

InstaMock is an AI-powered mock interview platform that simulates real technical interviews. Our AI interviewer conducts realistic interviews for System Design (HLD), Low Level Design (LLD), Data Structures & Algorithms (DSA), and Behavioral rounds. You get real-time feedback, live scoring, and detailed performance reports to help you prepare for your dream job at top tech companies.
Our AI interviewer uses advanced natural language processing to conduct realistic interviews. You speak naturally through your microphone, and the AI responds just like a real interviewer would. It asks follow-up questions, challenges your assumptions, and provides hints when needed. After the interview, you receive a comprehensive performance report with scores across multiple criteria.
Yes. AI mock interviews are free to practise - HLD, LLD, DSA and behavioural rounds, with scored feedback and no credit card. 1:1 sessions with a real interviewer are paid: a 15-minute guidance session is ₹149, one 60-minute mock interview is ₹499, and two mock interviews are ₹899.
InstaMock offers four types of mock interviews: 1) High Level Design (HLD) - System design interviews covering distributed systems, scalability, and architecture. 2) Low Level Design (LLD) - Object-oriented design and code architecture. 3) DSA - Data Structures & Algorithms coding problems. 4) Behavioral - Leadership principles and situational interview questions.
Each mock interview session is 45 minutes, simulating real interview conditions at top tech companies. This includes time for problem discussion, solution design, follow-up questions, and a brief Q&A session at the end.

1:1 Mock Interview with Experts

A 1:1 mock interview on InstaMock is a live, real-time interview session with an experienced engineer from top tech companies like Google, Amazon, Meta, and Microsoft. Unlike AI mock interviews, you get direct human feedback, personalized tips, and realistic interview pressure. Each 1:1 mock interview includes a video call, live coding or system design discussion, and detailed post-interview feedback.
To book a 1:1 mock interview: 1) Achieve the required DSA score (1000+) and LLD score (700+) on InstaMock. 2) Browse available expert interview panels. 3) Select a date and time slot. 4) Submit your booking request. 5) The panel member reviews and approves your request. 6) You receive a video meeting link to join your mock interview session. You can book up to 2 mock interviews at a time.
Our mock interview panelists are senior software engineers and engineering managers from top tech companies including Google, Amazon, Meta, Microsoft, Netflix, and other leading firms. Each panelist has extensive real-world interview experience both as interviewers and candidates, ensuring your mock interview closely mirrors actual FAANG interview rounds.
AI mock interviews are available 24/7 with unlimited attempts and instant feedback powered by AI. 1:1 expert mock interviews are live sessions with real industry professionals who provide nuanced, personalized feedback, evaluate your soft skills, and simulate real interview pressure. For best results, use AI mock interviews for daily practice and 1:1 expert mock interviews for final preparation before your actual interviews.
A 15-minute guidance session is ₹149. One 60-minute mock interview with a working engineer is ₹499, and a pack of two mock interviews is ₹899 (₹449.50 each). You pay once, pick a time in the next 7 days, and we assign the interviewer and send the Google Meet link. After the session you get written feedback from your interviewer.

System Design (HLD)

A High Level Design (HLD) interview, also known as System Design interview, tests your ability to design large-scale distributed systems. You'll be asked to design systems like WhatsApp, Netflix, Uber, or Twitter. The interview evaluates your understanding of scalability, availability, consistency, databases, caching, load balancing, and microservices architecture.
To prepare for System Design interviews: 1) Learn fundamental concepts like CAP theorem, load balancing, caching, database sharding, and microservices. 2) Practice designing popular systems (WhatsApp, Netflix, Uber, etc.). 3) Understand trade-offs between different architectural choices. 4) Practice with AI mock interviews on InstaMock to get real-time feedback on your design approach.
InstaMock offers 21+ System Design questions including: Design WhatsApp, Design Netflix, Design Uber, Design Twitter, Design Instagram, Design Amazon, Design URL Shortener, Design Rate Limiter, Design Notification System, Design Payment System, Design Spotify, Design YouTube, Design Dropbox, Design Google Maps, and many more.
HLD (High Level Design) focuses on overall system architecture - components, their interactions, data flow, scalability, and infrastructure. LLD (Low Level Design) focuses on detailed class design, object-oriented principles, design patterns, and actual code structure. HLD answers "what components do we need?" while LLD answers "how do we implement each component?"
For FAANG System Design interviews: 1) Master distributed systems concepts. 2) Practice 15-20 common system design problems. 3) Learn to communicate your design clearly. 4) Use InstaMock's AI mock interviews to simulate real FAANG interview conditions. 5) Review feedback and iterate on your approach. Companies like Google, Meta, Amazon, and Netflix heavily emphasize system design skills.

Low Level Design (LLD)

Low Level Design (LLD) interview tests your ability to design object-oriented systems with clean, maintainable code. You'll design systems like Parking Lot, Elevator System, Chess Game, or Library Management System. The interview evaluates your understanding of SOLID principles, design patterns, class relationships, and code organization.
LLD interviews cover: Object-Oriented Programming (OOP) concepts, SOLID principles (Single Responsibility, Open/Closed, Liskov Substitution, Interface Segregation, Dependency Inversion), Design Patterns (Singleton, Factory, Observer, Strategy, etc.), UML diagrams, class relationships (inheritance, composition, aggregation), and code structure best practices.
To prepare for LLD interviews: 1) Master OOP concepts and SOLID principles. 2) Learn common design patterns and when to use them. 3) Practice designing systems like Parking Lot, Elevator, ATM, Snake Game. 4) Focus on writing clean, extensible code. 5) Practice explaining your design decisions clearly during InstaMock mock interviews.
Common LLD interview questions include: Design Parking Lot, Design Elevator System, Design Library Management System, Design Snake and Ladder Game, Design Chess, Design ATM Machine, Design Hotel Booking System, Design Movie Ticket Booking (BookMyShow), Design Splitwise, and Design Food Ordering System.

Data Structures & Algorithms (DSA)

DSA (Data Structures & Algorithms) interview tests your problem-solving and coding skills. You'll solve algorithmic problems involving arrays, strings, linked lists, trees, graphs, dynamic programming, and more. The interview evaluates your ability to write efficient, bug-free code and analyze time/space complexity.
To prepare for DSA interviews: 1) Master fundamental data structures (arrays, linked lists, trees, graphs, heaps). 2) Learn common algorithms (sorting, searching, BFS, DFS, dynamic programming). 3) Practice 100-200 problems on different topics. 4) Focus on time and space complexity analysis. 5) Practice coding under time pressure with InstaMock AI interviews.
Key DSA topics for interviews: Arrays & Strings (Two Sum, Sliding Window), Binary Search, Linked Lists (reversal, cycle detection), Trees & BST (traversals, LCA), Graphs (BFS, DFS, shortest path), Dynamic Programming (1D & 2D DP), Stack & Queue, Heap/Priority Queue, Backtracking, and Greedy Algorithms.
For FAANG-level interviews, aim to solve 150-200 quality problems covering all major topics. Focus on understanding patterns rather than memorizing solutions. Categories to cover: 30+ Array/String problems, 20+ Tree problems, 15+ Graph problems, 25+ DP problems, 15+ Binary Search, and 10+ problems each for Stack, Heap, and Backtracking.
Best practices for DSA preparation: 1) Start with easy problems and gradually increase difficulty. 2) Learn patterns (sliding window, two pointers, BFS/DFS). 3) Code without IDE help first. 4) Analyze time/space complexity for every solution. 5) Practice explaining your approach aloud. 6) Use InstaMock for timed mock interviews to simulate real conditions.

FAANG Interview Preparation

For Google interviews: 1) Master DSA - Google asks 2-3 coding rounds with medium to hard problems. 2) Practice System Design - senior roles require designing Google-scale systems. 3) Prepare for Behavioral using Googleyness principles. 4) Expect 4-5 interview rounds including phone screen. 5) Practice with InstaMock to get comfortable with the interview format.
For Amazon interviews: 1) Master the 16 Leadership Principles - every question relates to them. 2) Prepare STAR format stories for behavioral questions. 3) Practice coding with focus on optimal solutions. 4) System Design is crucial for SDE-2 and above. 5) Expect Online Assessment + 4-5 onsite rounds (Loop).
For Meta interviews: 1) Strong focus on coding - expect 2 coding rounds with 2 problems each. 2) System Design for E5 and above. 3) Behavioral round focusing on Meta values. 4) 45-minute coding rounds with emphasis on speed and accuracy. 5) Practice on InstaMock to improve your coding speed and communication.
Typical FAANG interview process: 1) Online Assessment or Recruiter Call. 2) Phone/Video Technical Screen (1-2 coding problems). 3) Onsite/Virtual Onsite (4-6 rounds) including Coding, System Design, and Behavioral. 4) Hiring Committee Review. 5) Team Matching. 6) Offer. The entire process takes 4-8 weeks.
Preparation time depends on your current level: Beginners need 6-12 months of consistent practice. Intermediate developers need 3-6 months. Experienced developers may need 1-3 months of focused preparation. Aim for 2-3 hours of daily practice covering DSA, System Design, and behavioral questions.

Platform Features

InstaMock's AI provides multi-dimensional feedback: 1) Real-time scoring during the interview. 2) Detailed performance report after each session. 3) Strengths and areas for improvement. 4) Specific suggestions for better answers. 5) Comparison with ideal solutions. 6) Topic-wise analysis to identify weak areas.
Yes! InstaMock allows you to: 1) Choose specific interview types (HLD, LLD, DSA, Behavioral). 2) Select questions by topic (Arrays, Trees, Graphs, etc.). 3) Filter by difficulty (Easy, Medium, Hard). 4) Practice specific system design questions (WhatsApp, Netflix, Uber, etc.). 5) Focus on weak areas identified in previous sessions.
To use InstaMock, you need: 1) A computer with a modern web browser (Chrome, Firefox, Edge, Safari). 2) A working microphone for voice interviews. 3) Stable internet connection. 4) Optionally, a webcam for video recording of your sessions. No additional software installation is required.
Yes! InstaMock saves all your interview sessions. You can: 1) Review transcripts of your conversations. 2) See your scores and feedback. 3) Track improvement over time. 4) Compare performance across different topics. 5) Download performance reports for personal reference.
Absolutely! InstaMock is designed for all skill levels: 1) Beginners can start with easy problems and get guided feedback. 2) The AI adapts its questioning based on your responses. 3) Detailed explanations help you learn from mistakes. 4) Practice mode available for learning before formal mock interviews. 5) Topic-wise preparation guides for structured learning.

Interview Tips

Effective communication in technical interviews: 1) Think aloud - share your thought process. 2) Ask clarifying questions before coding. 3) Discuss trade-offs in your approach. 4) Walk through your solution with examples. 5) Mention time and space complexity. 6) Be open to hints and feedback. Practice this with InstaMock's AI interviewer.
Common interview mistakes: 1) Jumping into coding without understanding the problem. 2) Not asking clarifying questions. 3) Ignoring edge cases. 4) Poor time management. 5) Not testing your code. 6) Being defensive about feedback. 7) Not practicing enough mock interviews before the real thing.
To manage interview anxiety: 1) Practice extensively with mock interviews to build confidence. 2) Prepare a consistent warm-up routine. 3) Focus on the problem, not the outcome. 4) Take deep breaths when stuck. 5) Remember that interviewers want you to succeed. 6) Use InstaMock to simulate real conditions and reduce anxiety.
When stuck in an interview: 1) Don't panic - take a moment to think. 2) Verbalize what you're thinking and where you're stuck. 3) Try a brute force approach first. 4) Think about similar problems you've solved. 5) Ask for hints - interviewers expect this. 6) Break down the problem into smaller parts.

Related Topics

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