Learn METRO4 with Real Code Examples

Updated Nov 23, 2025

Introduction & Fundamentals Setup & Configuration Architecture & Deep Internals Performance & Security Development Workflow Learning & Career Growth Business & Strategy Examples

Performance Notes

Include only required components to reduce CSS/JS size

Use minified CSS/JS for production

Optimize images and assets

Leverage browser caching

Avoid unnecessary JS widgets for performance

Security Notes

Validate forms server-side

Avoid unsafe inline JS

Keep Metro 4 updated to latest version

Audit third-party widgets

Ensure secure initialization of interactive components

Monitoring Analytics

Audit CSS & JS bundle size

Test responsiveness on devices

Check interactive widgets

Monitor accessibility compliance

Track frontend performance

Code Quality

Consistent class usage

Maintain theme variable consistency

Avoid unnecessary widget overrides

Document JS widget usage

Ensure responsive and accessible layouts