We are using PHP on the backend maintaining best practices of OOP, including extensive usage of SOLID principles, modularity, loose coupling, DIP usage, approaches like MVC and so on.
It is completely different approach from lower / junior level of web-sites development where ones widely used PHP language without proper OOP and mostly practice functional code style and even "spaghetti-code", direct SQL queries and so on.
We are using AWS, again aiming to best cloud solution practices, and going to build complete cloud-based solution with auto-balancing of instances, deploying of instances close to end-user region, usage of queues, no-SQL DBs, in-memory DBs, sharding etc.
✔ Operation system - Unix / Linux
✔ Cloud - Amazon Web Services
✔ Web-server - Nginx
✔ On-premises - Private Data Centers
✔ DBMS - PostgreSQL 9.6 +
✔ Virtualization - VMWare / KVM
✔ Programming language - PHP 7.2 +
✔ Telemetry Storage - InfluxDB 1.7 + / ELK (ElasticSearch LogStash Kibana)
✔ Used framework - Yii2
✔ Hardware Monitoring - Zabbix
✔ Caching - Redis
✔ CI/CD - GitLab CI
✔ Task manager - Cron
✔ Dependency Control - Composer
✔ Load Balancing - HAProxy
✔ Knowledge Database - Confluence, Postman
✔ Server QUEUE - RabbitMQ 3.7 +