84%
use or plan to use AI
of Stack Overflow survey respondents use or plan to use AI tools in development.
The arena moved
The hard part is knowing what to ask for, what to trust, what to test, and what to change. AlgoArena makes that judgment visible and gives people somewhere to sharpen it.
One arena
Train through Builder, Compete, and guided courses.
Teach through synchronized classrooms and bounded help.
Test through replayable, evidence-linked assessments.
Quietlist
Builder chat
Build a calm weekly planning app for small teams. Keep it keyboard-first.
Built the responsive board, command palette, and local task persistence. The preview is ready to inspect.
Responsive planning board
Keyboard command palette
Local task persistence
Live Preview
Weekly planning workspace
Monday, July 29
The week is clear. Pick the next meaningful thing.
Today
5 tasks
In progress
3 tasks
Done
10 tasks
Today
Build apps, tools, and games in a browser workspace where chat, files, code, preview, and publishing remain in one inspectable system.
Open Builder
JaeSon07
Silver • 1,186 ranked Elo

CarsonL22 (You)
Silver • 1,242 ranked Elo
1# Pair Sum Exists2import sys34lines = sys.stdin.read().split("\n")5nums = list(map(int, lines[0].split()))6target = int(lines[1])78seen = set()9for x in nums:10 if target - x in seen:11 print("true")12 break13 seen.add(x)14else:15 print("false")
2 7 11 15 9
Pending...
true
Use Add to open editable input fields for edge cases before a full submit.
Race another person, work through guided reps, or chase your own best. The real IDE, judged tests, and Rena stay inside the training loop.
Explore CompeteQuietlist
Builder chat
Build a calm weekly planning app for small teams. Keep it keyboard-first.
Built the responsive board, command palette, and local task persistence. The preview is ready to inspect.
Responsive planning board
Keyboard command palette
Local task persistence
Live Preview
Weekly planning workspace
Monday, July 29
The week is clear. Pick the next meaningful thing.
Today
5 tasks
In progress
3 tasks
Done
10 tasks
Today
A skippable guided path will teach first-time builders through the real Builder workspace, then move from plain-language intent into files, tests, browser checks, and owned projects.
Explore Vibecoding Courses04 · Classroom
The host starts once. Students join from their own browsers. Questions, timers, coding, hints, and the debrief stay synchronized.
Join at algoarena.net/classroom
or enter code
CS2026
Game Settings
Questions
6
Time
10s to 20m per question
Topics: arrays, linked lists, strings
Waiting for a student to join...
Players
1 joinedYou are the host
Join a session
Enter the 6-character code from your host, then join the live room.
Classroom
Host live algorithm quizzes, let students code in the room, and debrief the exact concepts that need attention.
Open
18
SLA risk
4
Ack rate
92%
AI access is not the signal. Inspect how a candidate plans, directs models, changes files, tests behavior, searches sources, recovers, and takes ownership of the result.
Explore AssessmentsInterview-ready by design
Our questions cover the algorithmic patterns commonly asked at companies like these.
































Company logos are shown for identification only. AlgoArena is not affiliated with or endorsed by these companies.
The confidence gap
The future does not belong to people who avoid AI. It belongs to people who can direct it, inspect it, verify it, and explain what they kept.
84%
of Stack Overflow survey respondents use or plan to use AI tools in development.
51%
of professional developers report using AI tools in their daily workflow.
46%
vs 33% who trust it
More developers distrust AI output than trust it, which makes verification a core skill.
Play a project, see inside the code, or fork one to make it yours.
Publish a finished app, tool, or game. Anyone can try it, inspect the code, and fork it into a new direction.
Browse the ShowcaseOne shared system
AlgoArena connects building, practice, teaching, and assessment through the same underlying record of intent, action, evidence, and judgment.
Files, diffs, tests, and browser results stay attached to the work.
Prompts, models, permissions, tool calls, and decisions remain visible.
Running software must answer back through tests, search, and real interaction.
Learning and hiring judgments can point to the exact moment behind them.
From our users
Developers, founders, and CS students on practicing, competing, and getting ready for the interviews that count.
“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.”

Co-Founder, tryhermes.dev · CS & Math @ Swarthmore
“Working on AlgoArena was a great experience. The team is building something genuinely focused on improving how people learn and practice problem solving. I especially liked the clarity of vision and the speed at which ideas were being tested and shipped. It's a strong foundation, and I'm excited to see how it evolves.”

Founder, Startup Metric · CS @ ACE Engineering
“AlgoArena has transformed how I prepare for technical interviews. The platform's ranked 1v1 battles provide that real-world 'pressure' you can't get from standard coding sites. The AI-powered code analysis is a game-changer. It didn't just tell me my solution was wrong; it helped me understand the 'why' behind my logic errors. If you're serious about leveling up your DSA skills, this is the most interactive way to do it.”

Backend Developer · CSE @ Velammal
“AlgoArena has helped me manage my time better in solving logic puzzles, and it's a much less stressful resource than LeetCode. The practice interview helps me get a gauge at what a coding interview experience might look like, and helps me prep without having to memorize exactly what to say. It helps me build the tools for a successful interview.”
CS & Chinese @ Swarthmore
“AlgoArena has helped me develop my software development skills, and features such as the 1v1 battles have helped me develop problem solving skills under pressure. It has helped specifically with interview prep via the mock interviews with Rena and also with the constant skill building features.”

CS & Engineering @ Swarthmore
“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.”

Co-Founder, tryhermes.dev · CS & Math @ Swarthmore
“Working on AlgoArena was a great experience. The team is building something genuinely focused on improving how people learn and practice problem solving. I especially liked the clarity of vision and the speed at which ideas were being tested and shipped. It's a strong foundation, and I'm excited to see how it evolves.”

Founder, Startup Metric · CS @ ACE Engineering
“AlgoArena has transformed how I prepare for technical interviews. The platform's ranked 1v1 battles provide that real-world 'pressure' you can't get from standard coding sites. The AI-powered code analysis is a game-changer. It didn't just tell me my solution was wrong; it helped me understand the 'why' behind my logic errors. If you're serious about leveling up your DSA skills, this is the most interactive way to do it.”

Backend Developer · CSE @ Velammal
“AlgoArena has helped me manage my time better in solving logic puzzles, and it's a much less stressful resource than LeetCode. The practice interview helps me get a gauge at what a coding interview experience might look like, and helps me prep without having to memorize exactly what to say. It helps me build the tools for a successful interview.”
CS & Chinese @ Swarthmore
“AlgoArena has helped me develop my software development skills, and features such as the 1v1 battles have helped me develop problem solving skills under pressure. It has helped specifically with interview prep via the mock interviews with Rena and also with the constant skill building features.”

CS & Engineering @ Swarthmore
“AlgoArena feels quite different from other platforms, and it's really exciting to explore. This platform is very new and makes coding feel like a game. Competing with others and solving problems within a time limit really helps improve our speed and prepares us better for coding interviews. I also like that the questions are presented in a different and interesting way. The gamified interface makes the whole experience much more enjoyable and keeps me motivated to practice more.”

Blockchain Intern, li2edu · CSE @ GPREC
“I really enjoyed problem solving on AlgoArena. Practicing in a competitive environment makes the DSA journey more engaging.”

Java Backend Developer · MCA @ AKTU
“Legitimately stressful rushing to solve a LeetCode easy before your opponent. Fantastic interview prep. It definitely makes doing LeetCode problems more engaging and makes me try to finish them as fast as I can under pressure.”

Principal Scientist, Schrödinger · CS @ Stanford
“I like how easy it is to jump into practice. The platform feels well organized, and the UI is great. Great work on building it!”

Intern, DRDO · CSE @ MUJ
“AlgoArena feels quite different from other platforms, and it's really exciting to explore. This platform is very new and makes coding feel like a game. Competing with others and solving problems within a time limit really helps improve our speed and prepares us better for coding interviews. I also like that the questions are presented in a different and interesting way. The gamified interface makes the whole experience much more enjoyable and keeps me motivated to practice more.”

Blockchain Intern, li2edu · CSE @ GPREC
“I really enjoyed problem solving on AlgoArena. Practicing in a competitive environment makes the DSA journey more engaging.”

Java Backend Developer · MCA @ AKTU
“Legitimately stressful rushing to solve a LeetCode easy before your opponent. Fantastic interview prep. It definitely makes doing LeetCode problems more engaging and makes me try to finish them as fast as I can under pressure.”

Principal Scientist, Schrödinger · CS @ Stanford
“I like how easy it is to jump into practice. The platform feels well organized, and the UI is great. Great work on building it!”

Intern, DRDO · CSE @ MUJ
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