What it is
PHP is a server-side scripting language built for the web. Rasmus Lerdorf created it, and it now powers a large share of websites, including every WordPress site. The model is simple: a request comes in, a PHP script runs against the database, and HTML or JSON goes back out. That simplicity is a large part of why it spread so widely.
Modern PHP has types, a much faster engine than its early versions and a mature package manager in Composer. Frameworks such as CodeIgniter and Laravel add routing and database layers on top. It runs almost anywhere, most often behind Apache or nginx on Linux, and cheap hosting for it is available everywhere.
How I use it
- Taught myself PHP in 1999, while still at IBM.
- The Rental Pilot API is PHP on Ubuntu and Apache on EC2, with MySQL behind it.
- Built the Brikers ERP on a LAMP stack with SuiteCRM and Twilio.
- Built a Flex, PHP and MySQL investor CRM at Metal Mountain Resources, and a PHP and MySQL content management system at Marsh Canada.
PHP is the right tool when a system already runs on it and works. Rewriting a working back end is rarely worth the risk. I keep the Rental Pilot API in PHP because thousands of agreements reconcile through it every day, and I modernize around it instead of replacing it.
Questions
Do we need to rewrite our PHP system?
Usually not. Rental Pilot kept its PHP API and replaced the old UI with React screen by screen. The data kept reconciling the whole way.
Can you take over an older PHP application?
Yes. I have written PHP since 1999 and still read CodeIgniter, jQuery and Flash-era systems when modernizing them.