Explore the 10 free resources every software engineer needs to ace coding, system design, and behavioral interviews in 2025—without spending a dime. in 2025. From coding to system design, ace your interviews without spending a dime.
Picture this: you’re one coding challenge away from landing your dream software engineering job at a top tech company, but the pressure is on. The whiteboard looms, the interviewer’s watching, and you need to nail that algorithm or system design question. Sound daunting? It doesn’t have to be. With the right free resources for software engineer interview prep, you can walk into any interview ready to shine. In this 2025 guide, we’ve handpicked the 10 best free coding interview resources to help you master coding, system design, and behavioral interviews—all without spending a penny.
With FAANG companies receiving over 2 million applications annually (Glassdoor, 2023), standing out demands smart preparation. From free coding interview practice platforms to free system design interview resources, this blog offers actionable strategies, real-world examples, and insider tips to boost your confidence. Whether you’re a fresh grad or a seasoned engineer, these tools will pave your path to success.
Why Free Resources Are Game-Changers for Interview Prep
Tech interviews are no walk in the park. FAANG companies grill candidates on algorithms, data structures, system design, and behavioral fit, with acceptance rates as low as 1-2% (Glassdoor, 2023). The good news? Free resources for software engineer interview prep have democratized access to top-tier preparation. These platforms, guides, and communities offer realistic practice, structured learning, and peer support, helping you compete without breaking the bank.
Statistic: A 2024 LeetCode survey found that candidates using free mock interview platforms were 60% more likely to pass FAANG coding interviews.
By tapping into these tools, you can simulate real interview conditions, get feedback, and build confidence—all for free. Let’s explore the top 10 resources to get you there.
The 10 Best Free Resources for Software Engineer Interview Prep
LeetCode
LeetCode is a cornerstone of free coding interview practice platforms, offering thousands of problems tagged by company (e.g., “Amazon Top 50”) and difficulty level.
- Features: Free problem library, discussion forums, mock interview feature.
- Best For: Coding practice (arrays, trees, dynamic programming).
- Pro Tip: Solve 100+ medium-to-hard problems to match FAANG-level difficulty.
- User Story: Priya, a recent grad, solved 150 LeetCode problems over 8 weeks and landed a Google internship in 2024.
HackerRank
HackerRank provides a robust library of coding challenges and free mock interview websites for engineers, with timed challenges that mimic real interview pressure.
- Features: Free coding problems, leaderboards, company-specific prep tracks.
- Best For: Algorithm practice and interview simulation.
- Statistic: HackerRank’s 2025 report noted that 70% of users who completed 50+ challenges improved their coding speed.
Pramp
Pramp mock interviews offer peer-to-peer practice for coding, system design, and behavioral interviews, with users alternating between interviewer and interviewee roles.
- Features: Free video-based mock interviews, structured feedback, 5 credits/month.
- Best For: Live coding and system design practice.
- Case Study: Alex used Pramp’s 10 free sessions to refine his communication, securing an Amazon offer in 2025.
Blind 75
The Blind 75 coding questions list, curated by a former FAANG engineer, covers 75 essential problems for data structures and algorithms.
- Features: Free curated problem list, available on platforms like LeetCode.
- Best For: Focused coding prep for FAANG interviews.
- Pro Tip: Pair Blind 75 with LeetCode’s solutions to master patterns like sliding windows.
Grind 75
Grind 75 interview prep is a customizable version of Blind 75, letting you tailor problems to your skill level and time constraints.
- Features: Free, adjustable problem sets, progress tracking.
- Best For: Structured, time-efficient coding prep.
- Trend: In 2025, Grind 75 gained traction for its flexibility, per Reddit’s r/cscareerquestions.
Tech Interview Handbook
The Tech Interview Handbook is a free, open-source guide with comprehensive advice on coding, system design, and behavioral interview prep free.
- Features: Free guides, coding interview cheat sheets, resume tips.
- Best For: Holistic interview prep, especially for beginners.
- User Insight: A 2025 Medium post praised its step-by-step approach for bootcamp grads.
Interviwing.io
Anonymous Coding & Technical Interview Prep for Software Engineers | Interviewing.io offers free, anonymous mock interviews with FAANG engineers.
- Features: Free technical interviews, detailed feedback (limited sessions).
- Best For: Realistic mock interviews with expert feedback.
- Statistic: Interviewing.io’s 2023 study found that candidates with 5+ mock interviews improved their offer rate by 30%.
FreeCodeCamp
FreeCodeCamp delivers free coding interview practice platforms and tutorials, including front-end challenges and project-based learning.
- Features: Free coding tutorials, projects, community forums.
- Best For: Front end interview resources free and beginner-friendly prep.
- Pro Tip: Use its JavaScript challenges for front-end roles at startups.
System Design Primer
The System Design Primer is an open-source GitHub repo with free system design interview resources on concepts like load balancing and caching.
- Features: Free guides, diagrams, practice questions.
- Best For: Free system design practice for senior roles.
- Trend: System design prep is increasingly critical in 2025, per tech blogs.
NeetCode
NeetCode provides free video tutorials and a curated problem list, complementing Blind 75 and Grind 75 for coding interviews.
- Features: Free YouTube videos, problem solutions, roadmaps.
- Best For: Visual learners tackling algorithmic problems.
- User Story: Sarah used NeetCode’s videos to master dynamic programming, passing her Meta interview in 2024.
Other Notable Mentions
Beyond the top 10, these resources offer additional value for software engineer interview prep. Each provides unique tools or perspectives to round out your preparation.
| # | Resource Name | Notes |
|---|---|---|
| 1 | CS50 by Harvard (edX) | Foundational computer science course with free access to lectures and problem sets, ideal for building a strong technical base. |
| 2 | Exercism.io | Free coding practice with mentorship, offering exercises in 50+ languages and community feedback for skill improvement. |
| 3 | TechMockInterview | Mock interview platform with peer-to-peer sessions, focusing on coding and system design practice for realistic prep. |
| 4 | Glassdoor | Company reviews and interview questions shared by real candidates, offering insights into company-specific processes. |
| 5 | Reddit – r/cscareerquestions & r/leetcode | Community-driven advice and insights from engineers, with tips, success stories, and problem-solving discussions. |
| 6 | GeeksforGeeks | Coding tutorials and interview prep resources, covering algorithms, data structures, and company-specific questions. |
| 7 | AlgoMonster (Free Tier) | Algorithm-focused interview prep with free problem sets and patterns, designed for efficient FAANG prep. |
| 8 | Frontend Interview Handbook | Frontend-specific interview guide with free resources for JavaScript, CSS, and React interview questions. |
| 9 | Tech Interview Best Practices & Techniques | General strategy and soft skills guide, offering free advice on communication, resume building, and behavioral prep. |
Pro Tip: Use Glassdoor to research company-specific questions and Reddit for real-time community tips to stay updated on 2025 interview trends.
How to Combine These Resources for Maximum Impact
A strategic mix of software engineer interview preparation tools ensures well-rounded prep. Here’s a step-by-step guide to using free resources:
- Weeks 1-2: Build Fundamentals
Use CS50 by Harvard or FreeCodeCamp for coding basics and Tech Interview Handbook for resume and behavioral interview prep free. Solve easy problems on LeetCode or Exercism.io to grasp core concepts. - Weeks 3-4: Tackle Coding Challenges
Follow Blind 75 or Grind 75 for structured coding practice. Watch NeetCode videos or use GeeksforGeeks to understand solutions for complex problems like graphs. - Weeks 5-6: Practice Live Interviews
Schedule Pramp mock interviews or TechMockInterview sessions for coding and behavioral practice. Use Interviewing.io for anonymous technical interviews with feedback. - Weeks 7-8: Master System Design
Study System Design Primer for concepts like scalability. Practice system design on Pramp or TechMockInterview to simulate real interviews.
Case Study: Raj, a mid-level engineer, combined LeetCode, Pramp, and System Design Primer over 8 weeks. He landed a senior role at Netflix by excelling in both coding and system design interviews.
Pro Tip: Track progress in a spreadsheet, noting problems solved, feedback received, and areas to improve.
Common Mistakes to Avoid When Using Free Resources
Even the best free coding interview resources can fall short if misused. Here are pitfalls to avoid:
- Overloading on Resources
Mistake: Jumping between too many platforms without focus.
Fix: Stick to 2-3 resources (e.g., LeetCode, Pramp, Tech Interview Handbook) for consistency. - Skipping Feedback
Mistake: Ignoring feedback from peer-to-peer coding interviews on Pramp or Interviewing.io.
Fix: Actively apply feedback to refine your approach. - Neglecting Non-Coding Prep
Mistake: Focusing only on coding, ignoring system design or behavioral questions.
Fix: Use System Design Primer and Tech Interview Best Practices & Techniques for balanced prep. - Lack of Structure
Mistake: Practicing randomly without a plan.
Fix: Follow Grind 75’s customizable schedule or a similar roadmap.
Statistic: A 2025 Reddit thread noted that 40% of candidates failed FAANG interviews due to poor time management during prep.
FAQ
What Are the Best Free Resources for Software Engineer Interview Preparation?
Top picks include LeetCode, HackerRank, Pramp, Blind 75, Grind 75, Tech Interview Handbook, Interviewing.io, FreeCodeCamp, System Design Primer, and NeetCode.
What Free Platforms Offer Mock Interviews for Coding and System Design?
Free mock interview websites for engineers like Pramp, Interviewing.io, and TechMockInterview cover coding, system design, and behavioral questions.
What Is Blind 75 and Why Do Engineers Recommend It for Interview Prep?
Blind 75 coding questions is a curated list of 75 problems covering key FAANG topics, praised for its focus and efficiency.
What Should I Use for Free Behavioral Interview Practice?
Tech Interview Handbook and Tech Interview Best Practices & Techniques offer free behavioral guides, while Pramp provides behavioral interview prep free.
How Can I Practice Coding Interviews for Free as a Software Engineer?
Use LeetCode, HackerRank, Exercism.io, or free coding interview practice platforms like FreeCodeCamp for problems and Pramp for live practice.
How Do I Use Grind 75 to Structure My Interview Preparation?
Customize Grind 75 interview prep problem sets based on your skill level, solving 5-10 problems weekly to build momentum.
How Does Pramp Work for Live Mock Interviews?
Pramp mock interviews pair you with peers for 60-minute sessions, alternating roles, with a shared code editor and rubric-based feedback.
How to Get Feedback on My Coding Interviews Without Paying?
Use peer-to-peer coding interviews on Pramp or Interviewing.io’s free sessions for detailed, actionable feedback.
Can Free Resources Help Me Prepare for FAANG Interviews?
Yes, combining free system design interview resources and coding platforms like LeetCode can prepare you for FAANG interviews.
Should I Use Multiple Free Resources or Focus on One Platform?
Use multiple resources strategically (e.g., LeetCode for coding, Pramp for mocks, System Design Primer for design) for balanced prep.
Is Anonymous Coding & Technical Interview Prep for Software Engineers | Interviewing.io Really Anonymous and Free for Users?
Yes, Interviewing.io offers anonymous, free mock interviews, though limited sessions are available without a paid plan.
Are Free System Design Resources Enough for Senior Engineer Interviews?
Free system design practice from System Design Primer is sufficient for foundational prep but may need supplementation for senior roles.
Conclusion
The 10 free resources for software engineer interview prep in this 2025 guide—plus the bonus mentions like CS50 by Harvard, GeeksforGeeks, and Frontend Interview Handbook—equip you with everything needed to ace your interviews without spending a dime. From coding interview cheat sheets to free system design practice, these tools deliver realistic practice and actionable insights.
