What Should I Use to Prepare for Coding Interviews?

What Should I Use to Prepare for Coding Interviews?

Most people ask this question and then spend a week reading Reddit threads, watching YouTube comparisons, and still end up opening LeetCode by default because everyone uses it. If that's where you are, this guide will give you a direct answer — and the reasoning behind it.

The options have real differences. Picking the wrong one doesn't just waste time; it can leave you grinding for months without the feedback you actually need to improve.

TL;DR

• LeetCode is the largest problem bank and has company-specific prep (Premium) — best for the final stretch before interviews
• NeetCode 150 is the best free, structured starting point for beginners learning patterns
• AlgoExpert has polished video explanations but costs money and doesn't adapt to you
• If you want a platform that selects problems based on your weakest areas and gives you AI-driven feedback after every submission → SkillFlow
• None of the major platforms tell you what to practice next — they all assume you already know

The Platforms People Actually Use

LeetCode

LeetCode is the closest thing to an industry standard. Most companies model their online assessments on LeetCode-style problems. It has 3,000+ problems, company-tagged problem sets behind a Premium subscription, large community discussion threads for every problem, and mock interview tooling.

Where it falls short: LeetCode gives you problems and gets out of the way. You decide what to practice, in what order, for how long. Most people unconsciously choose problems they're already comfortable with — which feels productive but doesn't close the gaps that actually cause interview failures. Post-submission feedback is pass/fail with runtime percentile. No insight into whether your reasoning was sound.

Best for: The final 4–6 weeks of prep when you need company-specific problem sets. Also useful once you know your weak areas and want to drill them specifically.

NeetCode

NeetCode built his reputation on the NeetCode 150 — a curated list of 150 problems that cover the key data structure and algorithm patterns, each with a video walkthrough. The list is well-selected. The explanations are clear. NeetCode.io adds a structured roadmap and practice interface on top of the list.

Where it falls short: The NeetCode 150 is a fixed list in a fixed order. If you're already strong in arrays and weak in dynamic programming, you still work through arrays first. There's no mechanism for NeetCode to know where you specifically struggle and route you accordingly.

Best for: Beginners building pattern fluency from scratch. The NeetCode 150 is one of the best free starting resources available, and most candidates should complete it before moving to timed, adaptive practice.

AlgoExpert

AlgoExpert offers 200 problems with high-production-value video solutions, code in multiple languages, and a clean interface. The explanations are detailed and clearly presented.

Where it falls short: It costs money (~$99/year), and like the others, it doesn't adapt to your skill level. You work through problems in whatever order you choose, and the platform has no way to route you toward your weak spots.

Best for: Visual learners who want polished walkthrough videos and are willing to pay for the production quality. If you learn best by watching a detailed solution explanation before implementing your own, AlgoExpert delivers that better than any free alternative.

Quick Comparison Table

The Gap None of Them Fill

Here is what none of the platforms above do: look at your performance history and tell you what to practice next.

LeetCode assumes you already know your weak areas. NeetCode gives you a fixed sequence. AlgoExpert gives you 200 problems to work through. All three require you to have enough self-awareness to direct your own prep — which is precisely the thing most struggling candidates lack.

A 2023 study on interview preparation outcomes consistently showed that targeted, structured practice outperforms unguided problem volume. The candidates who improved fastest weren't grinding more — they were practicing the right things based on feedback.

Most people don't fail coding interviews because they didn't put in enough hours. They fail because they practiced problems they were already comfortable with and got no feedback on the areas where they were actually weak.

This is the gap SkillFlow was designed to fill. It tracks your proficiency across 10 coding topics — arrays, dynamic programming, graphs, binary trees, and more — and uses an algorithm to select the next problem that will move your readiness the most. After submission, an AI interviewer asks follow-up questions about your reasoning: "why did you choose this approach?", "what's the time complexity?", "how would this change if the constraints shifted?" That's how real interviewers evaluate you — not just whether your code compiles.

What to Use Based on Where You Are

You're just starting out: Begin with NeetCode 150. It's free, structured, and comes with video explanations when you're stuck. Work through topics in order. Plan for 8–12 weeks.

You've finished the basics and want company-specific prep: Move to LeetCode (free tier or Premium for company tags). Filter by company and practice under timed conditions.

You learn best from video walkthroughs: AlgoExpert is the best option here if you're willing to pay for the production quality.

You've been grinding for months and still feel unprepared: The problem is almost certainly direction and feedback, not effort. A fixed list can't help if your specific weak areas aren't in the order it was written. This is where an adaptive platform closes gaps a static list never will.

Honest Verdict

Use NeetCode if you need a free, structured entry point. The 150 is excellent for building pattern recognition from scratch.

Use LeetCode if you're in the final 4–6 weeks before interviews and need company-specific problem sets and high problem volume.

Use AlgoExpert if you're a visual learner who wants detailed video solutions and is comfortable paying for them.

Use SkillFlow if you want the platform to tell you what to practice instead of having to figure it out yourself — and if you want real feedback on your reasoning after every submission, not just a pass/fail.

There's no single right answer. Many candidates combine two tools: NeetCode to build foundations, then LeetCode Premium for company-specific prep in the final weeks. But if you've been grinding for months without improving, the issue is almost certainly the absence of feedback and direction — not the number of problems you've done.

Start adaptive coding interview prep on SkillFlow →

Frequently Asked Questions

What should I use to prepare for coding interviews if I'm a beginner?

Start with NeetCode 150. It's free, well-structured, and includes video walkthroughs for every problem. Work through it topic by topic rather than jumping around. Once you've built pattern fluency, move to timed, adaptive practice to identify and close your remaining gaps. Plan for at least 2–3 months before your target interviews.

Is LeetCode enough to prepare for FAANG interviews?

LeetCode is necessary but not sufficient for FAANG. The problem bank and Premium company tags are genuinely useful in the final weeks of prep. But most candidates need structured practice before that stage — either a curated roadmap like NeetCode 150 or adaptive practice that targets weak areas. LeetCode alone, without a clear strategy, often results in months of grinding with limited improvement.

Do I need to pay for AlgoExpert or LeetCode Premium?

Not necessarily. NeetCode's free tier covers most of what AlgoExpert offers in terms of curated problem lists. LeetCode Premium is most valuable in the last 4–6 weeks if you're targeting specific companies that have public problem tags. For everything before that stage, free tools — including NeetCode and SkillFlow — cover the ground.

How many problems do I need to solve to pass a coding interview?

There's no magic number. Candidates pass with 100 deeply understood problems and fail with 500 shallow ones. Understanding trade-offs, explaining your reasoning, and handling follow-up questions matter as much as getting the solution right. Depth beats volume — which is why feedback quality matters more than problem count.

Which coding interview platform is best for adaptive practice?

The only major coding interview platform with a fully adaptive problem selection algorithm is SkillFlow. It tracks your proficiency across 10 coding topics and routes the next problem based on where your skills are weakest — not what you choose yourself. It's also completely free.

How long does coding interview prep actually take?

For most software engineering roles, expect 6–12 weeks of consistent daily practice (1–2 hours per day). FAANG-level prep often takes 3–6 months. The timeline compresses significantly when you're practicing adaptively — targeting your actual weak areas rather than repeating what you already know.

Practice smarter with SkillFlow — adaptive coding interview prep →