One arena for both kinds of coding skill.
Grind sites test whether you can invert a binary tree. Modern interviews and modern jobs also test whether you can ship with AI in the loop. AlgoArena trains and measures both, and labels honestly what is live today versus still being built.
10,000+
problems
17
languages
1,500+
accounts
2,300+
matches played
Matches are 1v1 battles vs players and bots, replayable keystroke by keystroke.
How we compare
AlgoArena vs. the practice sites
Solo problem sets are where most platforms stop. AlgoArena adds live ranked competition, an AI coach, and classroom and hiring surfaces on top of the practice library.
AlgoArena |  LeetCode |  Kattis |  Project Euler | |
|---|---|---|---|---|
| Real-time 1v1 ranked battles | ||||
| Ranked ladder | Partial | |||
| Large problem library (10,000+) | 10,000+ | 3,000+ | 3,000+ | 900+ |
| AI tutor (Rena) | ||||
| Mock interviews | ||||
| Puzzle Rush speedruns | ||||
| Live classroom sessions | ||||
| AI-era hiring assessments | Early access | |||
| Beginner-friendly onboarding | Partial | |||
| Free to start |
From the arena
I interviewed at a Series A startup and the format was basically what AlgoArena trains you for. They didn't just test algorithms, they tested how I think about product and how well I use AI to build. That's how interviews actually work now. When I worked at Tesla and big techs, you're expected to use AI, no questions asked. AlgoArena is the only one I've found that actually measures the skill that matters today: how well you work with AI, not without it.
Jaehoon Son
Co-Founder, tryhermes.dev · CS & Math @ Swarthmore
Who it serves
Built for both sides of the interview
The same arena trains candidates, powers classrooms, and gives hiring teams evidence. Each surface carries an honest maturity label.
Students & candidates
Train for interviews that test both. Ranked duels build the classic rigor under pressure; guided practice and mock interviews build how you reason out loud.
- Ranked 1v1 battles vs players and bots
- 10,000+ problems across 17 languages
- Puzzle Rush, guided practice, and mock interviews
Educators
Turn lectures into live sessions. Host quizzes, watch answers land in real time, and debrief the exact concepts the room actually missed.
- Live quiz sessions with real-time answers
- Debriefs on the concepts students missed
- Custom assessments from the problem library
Hiring teams
See how candidates actually build with AI: planning, directing agents, verifying output, and shipping, with replayable evidence behind every score.
- Agentic work samples, not transcript homework
- Replayable prompt, edit, and test lineage
- Guided pilots today, waitlist for general access
Frequently asked
LeetCode is a strong solo practice library, and the comparison table above is honest about that. AlgoArena adds what solo grinding cannot: live ranked battles vs players and bots, classroom sessions for educators, and assessments built for hiring in the AI era, all on one account.
Prove both kinds of skill.
Start with ranked practice today. Classrooms, assessments, and the rest of the arena are one account away.