The following list contains resources about the PHP language, its internals, best practices and other various topics explained.
- wiki.php.net/internals/references - Excellent list with various resources, books, blog posts
- www.phpinternalsbook.com - covers both PHP 5 and PHP 7 internals
- phpinternals.net - a reference of internal symbols and also few articles
- externals.io - the PHP #internals email list accessible online
- phpinternals.news - Podcasts by Derick Rethans about PHP Internals
- derickrethans.nl - Derik Rethans
- nikic.github.io - Nikita Popov
- blog.ircmaxell.com - Anthony Ferrara
- schlueters.de/blog - Johannes Schlüter
- blog.golemon.com - Sara Golemon
- blog.jpauli.tech - Julien Pauli