Programming languages: PHP, JavaScript (JQuery), Java, C.
Frameworks: Yii2, Zend2, CakePhp3, Codeigniter3, Kohana, FuelPHP.
CMS: strong skills in Wordpress, eCommerce, custom CMS on Yii2 and on Zend2.
APIs: Google API, Youtube API, Social (Facebook, LinkedIn, Google+, Twitter), payment gateways (Paypal, Payson, Wirecard), Yandex API, Google analytics.
Technologies: RESTful, SOAP, Long-polling, Ajax, Oauth, Composer.
OOP, SOLID, RBAC, Events, AR, design patterns (MVC, ORM, DI etc).
Databases: MySQL, MySQLi, PostgreSQL, MongoDB.
SQL: Strong knowledge of SQL query language. Indexies, triggers, transactions, events, complex requests, replication, high performance queries, data normalization, full-text search.
System administration: debian based OS, cronjob, AWS (S3, EC2), version control (svn, git), dovecot, postfix, squid, gitosys, gitolite, ssh, mysql replication, apache, nginx.
Full stack LAMP and LEMP.
Server side caching: Memcache, Redis.
Tests: PHPUnit.
Version control: Git, SVN.