Programming Languages
PHP (14 years),
JavaScript (6 years),
Go (4 years),
Clojure (2 years),
Python (1 year),
basics of C++, Java
Databases
relational (MySQL, MariaDB, PostgreSQL), Graph oriented (Neo4j, Titan),
document oriented (CouchDB, MongoDB)
Operating Environments
Windows, Linux (Debian, Ubuntu, …),
Docker, AWS, Google Cloud, VirtualBox
Misc
Kafka, Redis, RabbitMQ, Icinga, Riemann, InfluxDB, Grafana
Version Control
Git, Mercurial, Subversion
Web-based application to manage time schedules for livestreaming events,
specifically for the gaming community
PHP, MariaDB, Silex
Web-based, highly extensible CMS with an emphasis on compatibility with
legacy servers and cloud environments
PHP, MySQL
Caching library implementing namespaced storage in a variety
of key-value based storages like Memcached, Redis et al.
PHP
Extensible chat bot for Twitch.tv
Node.js (version 1), Go (version 2)
Package to make NaCl easier to use for password-based encryption
Go, NaCl