AtCoder

Input—per 1M tokens

Output—per 1M tokens

Context—tokens

WeightsClosed

About

AtCoder is ranked #11 of 30 in coding challenge platforms on Inferse. It runs on Web. There is a free plan.

Compared on coding challenge platforms

Free plan: Yesatcoder.jp
Primary use: contestsatcoder.jp
Languages supported: C, C++, C#, Java, Python, Rust, Ruby, Go, Kotlin, Swift, JavaScript, TypeScript, PHP, Perl, Lua, Scala, Haskell, OCaml, Nim, Pascal, R, SQL, Prolog, PowerShell, Bash, Fortran, COBOL, Julia, Dart, Elixir, Erlang, F#, D, Crystal, Clojure, Common Lisp, Scheme, Visual Basic, Lean, LLVM IRatcoder.jp
Problem library size: 5,000 problemsatcoder.jp
Solution explanations: Yesatcoder.jp

Facts

What it does: AtCoder is a competitive-programming contest site where users solve programming problems competitively.info.atcoder.jp · 1 Oct 2026
Contest types: AtCoder offers Algorithm Contest and Heuristic Contest formats.info.atcoder.jp · 1 Oct 2026
Browser execution: Users can execute source code in a browser without building a local programming environment.info.atcoder.jp · 1 Oct 2026
Contest schedule: Beginner Contests run weekly, Regular Contests about monthly, Grand Contests five to six times yearly, and heuristic contests about monthly.info.atcoder.jp · 1 Oct 2026
Scale: AtCoder states that about 200,000 people are registered and about 10,000 users participate in real-time contests weekly.info.atcoder.jp · 1 Oct 2026
Practice library: The service provides about 5,000 past problems and extensive explanations.info.atcoder.jp · 1 Oct 2026
Programming languages: Commonly used languages include C++, Python, Rust, Java, and C#; AtCoder supports nearly all major programming languages.info.atcoder.jp · 1 Oct 2026
Ratings: Real-time participation in Algorithm or Heuristic contests changes a user's AtCoder rating.info.atcoder.jp · 1 Oct 2026
Recruiting integration: AtCoder Jobs lets users apply to companies using their AtCoder rating, including for new graduate, experienced, part-time, and internship roles.info.atcoder.jp · 1 Oct 2026
Skill assessment: PAST is an online algorithm skills test available in Japanese and English, with problems updated every six months.info.atcoder.jp · 1 Oct 2026
Analytics integration: AtCoder uses Google Analytics to measure access trends and improve its website.atcoder.jp · 1 Oct 2026
Privacy management: AtCoder says its personal-information protection management system conforms to JIS Q 15001.atcoder.jp · 1 Oct 2026
Third-party disclosure: AtCoder says it does not provide personal information to third parties without user consent except where required by law.atcoder.jp · 1 Oct 2026
AI-training opt-out: Users can opt out globally or per submission from licensing submitted source code to AI companies for training data.atcoder.jp · 1 Oct 2026
Account limit: The terms allow one account per member and prohibit transferring, lending, or sharing an account.atcoder.jp · 1 Oct 2026