Here is my list of recommended articles to read in free time. It collects php, javascript, design patterns and different architecture approaches. Some articles are for high level developers, and some for beginners. I put a comments to recognize them.
Backend
- Refactoring.com - It’s not only about PHP and will be useful to any developer
- PHP The Right Wat - Online reference for beginners
- HTTP request life cycle - How HTTP works
- CQRS - An introduction to CQRS from Martin Fowler. High level
- Martin Fowler - Articles from the icon of software design. Mid level
- 30 Regex Code Snippets All Web Developers Should Know - Useful reference for beginners
- How PHP Executes – from Source Code to Rende - Good description of PHP from inside for beginners
- Bobby Tales - How to prevent SQL injections for beginners
- MySQL interview questions - Refresh your knowledges, for beginners
Frontend
- 2017 is the year that front-end developers should go back and master the basics - A really good overview of trends
Other
- 19 Tips For Everyday Git Use - collection of useful git tips