Be among the first to experience real-time competitive programming. Create your account and start battling today.
AlgoArena is a competitive programming platform built around real-time 1v1 coding battles and structured practice. You solve algorithmic problems under time pressure, get instant verdicts from an input-based judge, and climb an ELO-style ladder as you improve. If you’ve used platforms like LeetCode or Codeforces, AlgoArena is designed to feel familiar—while adding the adrenaline of live competition.
Each battle gives both players the same problem and the same constraints. You write code in the browser, run tests, and submit. The judge validates your output against hidden test cases and returns a verdict. When you finish, you can review performance metrics and learn from what worked (or what didn’t).
Start here: How it Works.
Prefer to train before battling? Use practice mode to build fundamentals: arrays, strings, hashing, two pointers, trees, graphs, dynamic programming, and more. The goal is to help you progress from “I can solve easy problems” to “I can consistently solve under pressure.”
Explore: Practice Problems.
Input-based problems mirror real competitive programming: your program reads from stdin and writes to stdout. This style supports many languages, enables stronger hidden tests, and makes it easy to generate large cases that reveal inefficient solutions.
Read the rationale: Why Input-Based?
Is AlgoArena free? Yes—practice and core features are available for free, with optional upgrades for power users.
What languages are supported? Multiple languages (Python, JavaScript/TypeScript, Java, C++, and more) with consistent judging.
How do rankings work? Battles update your rating based on opponent strength, similar to ELO systems used in competitive games.
Do I need an account? You can browse public pages without one, but you’ll need an account to battle, submit, and track progress.