1. Databases: MySQL, PostgreSQL – administration, optimization, sharding, replication; redis, elasticsearch, MSSQL, HANA
2. Backend: php, *mq, sphinx, nodejs, java; bitrix, yii2, laravel, symfony, spring, RESTful API, PSR, SOLID, DRY, KISS
4. Frontend: react, typescript, vue.js, ES5/6, vuex, redux, webrtc, phaser, webgl, CSS/HTML – HTML 4.01 Strict, HTML5, bootstrap, jQuery, ajax, scss
5. Mobile: react-native, vue-native, java, expo go, quasar
6. Misc: C – memory, fs, socket, stream, audio. C#/C++ - OpenGL, Qt, arduino, VBA – DAO, XML, ADO
7. Administration: Linux Debian, nginx, php-fpm, mysql, pma, squid, postfix, bind9, ssl, amavis, clamav, asterisk, dovecot, postfix, proftpd, git, docker, monnit, virtualbox, redmine, bash, php, k8s, gitlab, bb