Public beta — servers are in Seoul for now (you may notice some latency). US region coming at full launch.
Practice coding
with your AI, not against it.
Everyone codes with AI now — but nowhere lets you practice or prove it. ThinkCode gives you a zero-setup playground with Claude Code & Codex built in, and problems designed for the AI era.
Zero-setup playground
A personal container in your browser: editor, terminal, live preview. Run claude or codex and sign in with your own subscription — once. Your workspace and login persist.
AI-native problems
Not just algorithms. Messy 1,500-line server logs, ledgers with injected inconsistencies, and exploration tasks where the spec is hidden in the data — problems where directing and verifying your AI is the skill.
Process over output
We track how you got there — iterations, runs, verification habits. A one-shot paste and a debugged solution are not the same skill, and your record shows it.
Build real things
Project tasks (a guestbook app, a Pomodoro timer) built step-by-step with your AI in a live-preview workspace. Requirements panel included.
How it works
1Sign up free — no card, no install
2Open the playground and log in your Claude / ChatGPT account (one time)
3Pick a problem — algorithms solo, vibe tasks with your AI
4Submit from the IDE and get judged instantly
FAQ
Do I need an API key?
No. You sign in with your existing Claude or ChatGPT subscription inside your playground terminal — the same way you would on your laptop.
What does it cost?
The playground and problems are free. Your AI usage runs on your own plan.
Is using AI cheating?
Not here. Vibe tasks are designed for it — the hidden test cases measure whether you specified, directed, and verified correctly. Algorithm problems stay AI-free with a one-hint budget.
Think it, Code it — ThinkCode