CodePen

CodePen is a playground for front-end code — write HTML/CSS/JS and see results instantly. Developers worldwide publish motion experiments, component demos, and creative cases there. When you wonder “how is this effect done?”, chances are someone has already done it on CodePen and shared the code.

1. Search with effect keywords (“hover effect”, “particles”, “scroll animation”) and sort by popularity for the gems.
2. Open a pen and check forks and comments to gauge quality.
3. Click “fork” to remix a good effect into your own.
4. Mind each pen's license — CodePen's default is permissive, but some authors add their own terms.

• Instant render with zero setup
• A huge public gallery with viewable source
• Supports mainstream front-end libraries via CDN
• Collections make it easy to build an inspiration library