Master coding interviews with AI.
The only platform that combines LeetCode-style problems, AI pair programming, spaced repetition and skill analytics — all free.
Just need a scratchpad? Run code instantly in the Compiler →
def maxProfit(prices):
min_price = float("inf")
max_profit = 0
for price in prices:
min_price = min(min_price, price)
max_profit = max(max_profit, price - min_price)
return max_profitEngineers at world-class companies practice here
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Problems solved daily
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Languages supported
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AI-powered tools
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Platform features
27+ features. Zero paywalls.
One platform for algorithms, the instant compiler, AI tools, community and analytics. Swipe through the highlights.
VS Code–style editor
Full IntelliSense, Vim mode, 12 languages, hidden test cases and instant verdicts — zero config.
const seen = new Map<number, number>();
for (let i = 0; i < nums.length; i++) {
const need = target - nums[i];
if (seen.has(need)) return [seen.get(need)!, i];
seen.set(nums[i], i);
}AI Mentor
Progressive hints that never spoil the answer.
Streaks & gamification
XP, levels and badges keep daily practice consistent.
Skill analytics
See exactly where to focus next.
Spaced repetition
SM-2 resurfaces problems at the perfect moment.
Share-ready by default
Every link unfurls into a branded Open Graph & Twitter card.
Instant online compiler
Skip the boilerplate. Open a blank editor, paste code in any of 12 languages, pipe in custom stdin, and run it in a secure cloud sandbox — no problem, no test cases, no local setup.
name = input()
print(f"Hello, {name}!")
for i in range(3):
print(i * i)9 AI tools. One platform.
From personalized coaching to pair programming — AI is woven into every part of your practice.
Learning Coach
Personalized guidance for your weak areas
Pair Programmer
Conversational, real-time coding help
Roadmap Generator
A study path toward your target role
Resume Analyzer
Feedback tuned to engineering roles
Code Reviewer
Correctness, style and edge cases
Complexity Visualizer
Big-O for any snippet, explained
From zero to offer in three steps
Create your free account
Sign up with email, Google or GitHub. Pick your track: DSA, Frontend, or both. Takes 30 seconds.
Solve, practice, and learn
Code in a full editor. The AI mentor gives hints. Spaced repetition locks in patterns.
Level up and get hired
Earn XP, keep streaks, climb leaderboards, and walk into any interview prepared.
122+ real interview questions, ready to run.
DSA classics, JavaScript deep-dives and React pattern exercises — every problem executes against hidden test cases in the cloud.
Browse All ProblemsLoved by thousands of coders
“The AI mentor is the closest thing to a senior engineer next to you. Finally internalized sliding window.”
“Every other platform ignores frontend folks. The sandbox challenges with AI design review are exactly what I needed.”
“94-day streak and counting — went from failing easies to clearing mediums in one sitting.”
“Pair Programmer plus spaced repetition changed how I retain algorithms. Stopped forgetting patterns.”
“Generated my entire 8-week study plan in 30 seconds. It even accounted for my weak topics.”
“Weakness detection put my graph acceptance at 20%. Three weeks later it's 85%. Data-driven practice works.”
Start free, level up fast.
7-day free trial on all paid plans. No credit card required.
Frequently asked
Yes. Problems, the online compiler, frontend challenges, contests, roadmaps, all 9 AI tools and the forum are completely free. Just create an account.
Your next offer starts now.
Free forever. 27+ features. 9 AI tools. No credit card — just you, the editor, and an AI mentor that never sleeps.