TL;DR: I built SkillFlow because I experienced the same frustration most developers never name directly: not the difficulty of the problems, but the paralysis of not knowing which problem to practice next. LeetCode has 3,000 problems. Even the best curated lists have 150. Nobody tells you where you specifically should start, what your actual gaps are, or what to do next based on how you performed today. SkillFlow is the answer to that specific problem.
It Started with a Simple Question I Could Not Answer
When I started preparing for technical interviews, I did what every developer does. I opened LeetCode.
And then I sat there.
Not because the problems were too hard. Not because I did not know data structures. But because I had no idea which problem to open first.
LeetCode has over 3,000 problems. The filter options are difficulty, topic, and company. None of those tell you what you personally need to practice right now. You pick something, solve it, and then face the exact same question again: okay, what next?
So I did what most developers do when they feel lost in LeetCode. I went looking for a list.
The List Problem
The most recommended starting point is the Blind 75. Then I heard about NeetCode 150. Both are genuinely good resources. They filter the problem space down to what matters and give you a starting point.
But here is the thing nobody says out loud about following a list: even with 150 problems in front of you, the question is still there. Which one do I do today? Do I go in order? Do I skip the ones I find easy? If I struggle with a problem, do I move on or stay on it? If I come back to the list tomorrow, where do I pick up?
A list gives you a smaller version of the same problem. It does not tell you what you specifically need. It tells you what a generic developer needs. And you are not a generic developer. You have specific strengths and specific gaps that are different from every other person working through the same list.
I found myself spending more mental energy deciding what to practice than actually practicing. And when I did practice, I had no way of knowing whether I was making progress on the things that actually mattered or just reinforcing what I already knew.
The Gap Nobody Was Solving
The more I thought about it, the clearer the problem became.
Every developer I talked to had the same experience. They were putting in the hours. They were solving problems consistently. But they could not tell you with any confidence which areas they were genuinely weak in, which topics were costing them accuracy, or whether their prep time was going toward the gaps that would actually affect their interview outcome.
Most prep platforms track one thing: how many problems you have solved. That number tells you almost nothing useful. A developer who has solved 200 problems in their strongest categories is less prepared than a developer who has solved 80 problems spread deliberately across their actual weak spots.
The problem was not that developers were not working hard enough. The problem was that nobody was telling them what to work on.
What SkillFlow Does Differently
That is the problem SkillFlow is built to solve.
Instead of presenting you with a list and leaving the decisions to you, SkillFlow tracks your performance across every session and uses that data to determine what you practice next. If your sliding window accuracy is strong but your dynamic programming accuracy is weak, you get routed toward dynamic programming problems, not more sliding window.
You stop guessing. You stop spending mental energy on the meta-question of what to practice. You open the platform and it tells you exactly where to go based on where you actually are.
The result is that your prep time goes toward the gaps that will affect your interview outcome rather than the topics you are already comfortable with. Every session is the highest-leverage session you could have had that day.
You can get started for free at SkillFlow.
Why This Problem Does Not Get Talked About
There is a reason the "what should I practice next" problem does not come up much in prep discussions. It feels embarrassing to admit.
Saying you failed an interview because a problem was too hard is explainable. Saying you are not sure what to practice sounds like a planning failure, something you should just figure out yourself.
But it is not a planning failure. It is a data problem. You cannot know your weak spots without tracking your performance over time. You cannot prioritize correctly without knowing which areas have the highest gap between your current accuracy and what an interview actually requires. That is not information a developer can reliably generate through self-assessment.
The developers who prep most efficiently are not the ones who are better at planning. They are the ones who have a system that makes the right decisions for them. That is what I wanted to build.
What I Hope SkillFlow Does for Developers
The goal was never to build another problem library. There are already more problems than any developer could solve in a lifetime.
The goal was to build something that removes the friction between opening your laptop and doing the highest-value prep session you could do today. Something that makes the question "what should I practice next" disappear entirely.
If you have ever sat in front of LeetCode not knowing where to start, or followed a list and still felt like you were guessing, that is exactly the feeling SkillFlow is built to fix.
Key Takeaways
- The most common friction point in coding interview prep is not problem difficulty. It is not knowing which problem to practice next based on your actual performance.
- Curated lists like NeetCode 150 and Blind 75 solve the volume problem but not the personalization problem. They tell you what a generic developer needs, not what you specifically need today.
- Tracking solved problem counts is a poor proxy for interview readiness. What matters is your accuracy and speed across each problem category, and whether your prep time is targeting your actual weak spots.
- SkillFlow is built to remove the "what do I practice next" decision entirely by routing your sessions based on real performance data.
- The developers who prep most efficiently are not better planners. They have a system that makes the right decisions for them.
Frequently Asked Questions
What is SkillFlow?
SkillFlow is a free adaptive coding interview prep platform that personalizes your practice based on your real performance data. Instead of picking your own problems or following a static list, SkillFlow tracks your accuracy and speed across problem categories and tells you exactly what to practice next based on where your gaps actually are.
What problem does SkillFlow solve?
SkillFlow solves the decision problem in interview prep. Most platforms give you a library of problems and leave the decisions to you. That creates constant friction around the question of what to practice next, and it means most developers spend their prep time reinforcing what they already know rather than closing the gaps that will affect their interview outcome. SkillFlow removes that decision entirely.
Why is not knowing what to practice such a big issue?
Because prep time is limited and every session spent on a topic you are already strong in is a session not spent closing a real gap. Without performance data, developers cannot reliably identify which areas they are weakest in or which topics are most likely to cost them accuracy in an actual interview. Most developers overestimate their strengths and underestimate their gaps because self-assessment is unreliable without objective tracking.
How is SkillFlow different from NeetCode or LeetCode?
LeetCode is a problem library. NeetCode adds structure and video explanations on top of a curated list. Both are valuable. Neither adapts to your individual performance. SkillFlow is not a problem library or a curated list. It is a system that tracks how you perform across every session and adjusts what you practice next based on that data. The goal is to make every session your highest-leverage session possible.
Is SkillFlow free?
Yes. SkillFlow is free to use. You can get started at skillflow.dev.
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