Interview Prep Sites You Should Know

Software engineering interviews are no joke. Whether you’re brushing up for Big Tech, startups, or anything in between, having the right resources makes all the difference. Here are some of the most popular and effective websites that I use to prepare for technical interviews.

This list is far from exhaustive, but it should give you a solid start. If you think I’ve missed a gem or have corrections, my inbox is always open — you’ll find the contact info at the bottom.

Content

Programming:

  1. LeetCode
  2. HackerRank
  3. Hack2Hire
  4. Blind 75 & NeetCode

System Design & OOD:

  1. ByteByteGo by Alex Xu
  2. System Design Primer (GitHub)
  3. Grokking the System Design Interview

More resources for your reference:

  1. Codeforces
  2. CodeSignal
  3. AlgoExpert
  4. Interviewing.io
  5. Exercism
  6. GeeksforGeeks
  7. Pramp
  8. Object-Oriented Design Interview (Educative)
  9. High Scalability Blog

Programming

LeetCode

Probably the most popular site among job seekers preparing for coding interviews. LeetCode offers a massive collection of algorithm and data structure problems, categorized by topic and company.

Features:

  • Difficulty levels: Easy, Medium, Hard
  • Discuss section where users share solutions and interview experiences
  • Company-specific problem tags (e.g., Google, Amazon)
  • Contest mode for timed problems
  • Paid premium for access to more problems and mock interviews

🔗 https://leetcode.com/

HackerRank

HackerRank provides structured challenges for algorithms, data structures, SQL, functional programming, and more. Many companies use it as part of their online assessments.

Features:

  • Interactive coding environment
  • Certification paths (e.g., Python, Java, Problem Solving)
  • Practice by domain (AI, Security, etc.)
  • Interview preparation kits

🔗 https://www.hackerrank.com/

Hack2Hire

Hack2Hire provides one of the most convenient and quickest ways to prepare the real coding questions for tech companies.

Features:

  • All questions are extracted from real OA/screening/VO interviews
  • Each question are tagged with companies and methods
  • Every question’s solution and explanation has been cross-validated by experienced SDE and AI
  • Live coding IDE and free LC question posts

🔗 https://www.hack2hire.com/

Blind 75 & NeetCode

These aren’t platforms but curated lists. They provide must-do problems for technical interviews.

Features:

  • Blind 75 is a set of 75 hand-picked problems based on frequency in top company interviews
  • NeetCode offers structured playlists and YouTube explanations
  • Ideal if you want a focused, no-fluff study plan

🔗 https://neetcode.io/
🔗 https://www.techinterviewhandbook.org/grind75

System Design & OOD

ByteByteGo by Alex Xu

Created by the author of the best-selling “System Design Interview” book series. Offers paid and free content.

Features:

  • High-quality animated videos on system design concepts
  • Blog posts and newsletter content explaining real-world systems
  • Books that dive deep into system design problems with architecture diagrams
  • Also available on YouTube

🔗 https://bytebytego.com/
🔗 https://www.youtube.com/c/ByteByteGo

System Design Primer (GitHub)

An open-source goldmine. This repo is one of the most comprehensive resources for learning how to design scalable systems.

Features:

  • Covers key topics like load balancing, sharding, caching, and more
  • Real-world design problems (e.g., design Twitter, URL shortener)
  • Visual diagrams and trade-off discussions
  • Perfect for both beginners and experienced engineers

🔗 https://github.com/donnemartin/system-design-primer

Grokking the System Design Interview

A paid, interactive course that walks through common system design problems in an easy-to-understand manner.

Features:

  • Step-by-step solutions to problems like designing Facebook, Netflix, or Dropbox
  • Great balance of theory and practical architecture diagrams
  • Bite-sized lessons with illustrations
  • Especially useful for people who struggle with structuring their thoughts

🔗 https://www.educative.io/courses/grokking-the-system-design-interview

More Resources

Object-Oriented Design Interview (Educative)

If your interview has a heavy emphasis on OOD, this course is a great pick. It focuses on how to structure class-based solutions.

Features:

  • Detailed walkthroughs of OOD questions like designing a parking lot or elevator
  • Covers SOLID principles, UML, design patterns
  • Code-based explanations in Java (but transferable to other languages)
  • Ideal for companies like Amazon or Google that ask OOD questions

🔗 https://www.educative.io/courses/grokking-the-object-oriented-design-interview

High Scalability Blog

A long-running blog that documents architecture and scalability decisions from real-world companies.

Features:

  • “How They Do It” posts about companies like Uber, LinkedIn, Amazon
  • Deep dives into distributed system patterns
  • Good for understanding production-grade architecture choices
  • More advanced, great complement to system design learning

🔗 http://highscalability.com/

Codeforces

Codeforces is more competitive-programming oriented. It’s great if you want to sharpen your problem-solving speed and accuracy.

Features:

  • Regular contests and rating system
  • Editorials for problems
  • Focus on algorithmic thinking over interview-style questions
  • Active international community

🔗 https://codeforces.com/

CodeSignal

Used by some companies to assess coding skills via gamified assessments.

Features:

  • General Coding Assessment (GCA) used by companies
  • Arcade mode to practice with fun, gamified challenges
  • Certified assessments and ranking

🔗 https://codesignal.com/

AlgoExpert

A paid platform focused on technical interview prep with a curated set of 160+ problems and detailed video explanations.

Features:

  • Structured learning with categorized topics
  • Behavioral interview prep and system design content
  • Ideal for those who prefer video explanations over reading

🔗 https://www.algoexpert.io/

Interviewing.io

If you want to simulate a real interview, this is the platform. It offers mock interviews with engineers from top companies.

Features:

  • Anonymous mock interviews
  • Real feedback from interviewers
  • Focus on behavioral and technical rounds
  • Free and paid options

🔗 https://interviewing.io/

Exercism

Exercism is perfect if you’re also brushing up on programming languages. It focuses on mentorship-based learning.

Features:

  • Practice exercises across 60+ languages
  • Human mentorship for feedback
  • Great for strengthening fundamentals

🔗 https://exercism.org/

GeeksforGeeks

A goldmine of CS theory, data structures, algorithms, and real-life coding problems.

Features:

  • Well-written explanations and tutorials
  • Practice platform for coding questions
  • Interview experiences shared by users
  • Topic-specific study plans

🔗 https://www.geeksforgeeks.org/

Pramp

Short for “Practice Makes Perfect,” Pramp connects you with peers for free live mock interviews.

Features:

  • Peer-to-peer interviews with shared coding editor
  • Questions in data structures, algorithms, system design, and more
  • Great for improving communication and whiteboard-style coding

🔗 https://www.pramp.com/

Final Words (Mainly for myself)

Take your time, be consistent, and don’t get discouraged by tough problems and rejections. Like Rome wasn’t built in a day, Interview prep is a marathon, not a sprint.