- Linux (Ubuntu/Centos), OSX, Windows, iOS,Android (HTML5/Cordova)

- Multimedia (Video, Image, Audio) Transcoding, meta data

- manipulation Web Framework(Django) / Rest/custom API Server

- Distributed Task Queue / Server (Linux,OSX only)

- Database (Oracle, MySQL, PostgreSQL, SQLite) NoSQL (Redis, InfluxDB)

- Excel, CSV, XML, JSON, YML etc.

- Deploy, DevOps (Ansible)

- Network (SMTP/POP, S/FTP, RSYNC, NFS/Samba, SSH, TCP/IP, UDP) / Serial Communication

- Logging (Fluentd)

- Git/SVN

- Signal Processing (video/sound/electric pulse)

- Radio Frequency Control (RFID/RC)

- PCB (printed circuit board) / embedded board / Raspberry Pi