Attach CSS, JavaScript, images, fonts, JSON, CSV or SQL files, then use them from your code by filename — for example <link rel="stylesheet" href="style.css">, open('data.csv') or include 'lib.php'. They stay on this device, and Save downloads them together with your code as a .zip.
Code
Output
How It Works
1. Pick a Language
Use the dropdown above to switch between HTML/CSS/JS, Python, SQL, and PHP. Your code in each language is saved separately.
2. Run your Code
Click Run to see your output instantly on the right (or below, on smaller screens) — no setup or server required.
3. Diagnose Issues
Stuck on an error? Click Diagnose for an AI-assisted, beginner-friendly explanation of what's wrong and how to fix it.
4. Save or Upload
Download your work as a file any time, or upload an existing file from your device to keep working on it.
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