Operating systems Linux, KVM, vSphere, HyperV, MacOS, AIX, SunOS, DOS/Windows9x/NT/2000/XP
Sectors IT consulter, pharmaceutical industry, insurance, bank, leasing, authority, press agency, mineral oil industry, tax consulting
Databases Firestore, mongodb, DB2, Oracle, H2, Informix, MySQL, PostgreSQL, sapdb, ADABAS D, MS-SQL Server, MS-Access, dBase, Derby, HSQL
Development environments IntelliJ, Visual Studio Code, Visual Studio, XCode, Eclipse, Netbeans, Oracle JDeveloper und TopLink Mapping Workbench, Visual Age for Java, JBuilder, VisualCafe, Borland C, Delphi, JDK, GNU C/C++, RationalRose/MS-Visual Modeler, Visual Basic and VBA, Visual C++
Methods Domain Driven Design, Design Thinking, Personas, UX-Maps, OOA, OOD, OOP, Prototyping, Informationsbedarfsanalyse, Analyse DV-Technik, Entwurf Systemschnittstellen, Datenbankentwurf konzeptionell und physikalisch, Entwurf Klassenmodelle, Anwendungsverteilung in Softwarekomponenten
Networks

Wireguard VPN, Websockets/STOMP, IoT/MQTT, Routing, NAT, X-Protokoll, Einrichtung diverser Netzdienste, wie z. B. bootp, http, ftp, smb, mail (SMTP, imap4 u. pop3)
Middleware

Spring Boot, Micronaut, Quarkus, Node.js, NodeRed, nginx, haproxy, JBoss/Wildfly, Apache-Webserver, JEE, EJB, EJB3, CORBA, CICS, UNIKIX, Web Services/REST/SOAP, Sockets
products and frameworks AXON/Eventsourcing, github, gitlab, JIRA, Confluence, Bitbucket, GIT, SVN, CVS, EclipseLink, Oracle SQL-Developer Tomcat, YourKit Java Profiler, BugZilla, Mantis, jboss, Java WEB-Start, Ant, XDoclet, ErWin, KDE, Gnome, VMware, Star-/Openoffice, Mambo/Joomla/typo3 Content Management, Wiki, Bind, Squid, SSH, Webmin, MS-Office, The Gimp
DevOps/Cloud Docker, Kubernetes, jenkins, Google Clout Platform, Azure, AWS, Cloudinit, Ansible, Vagrant, Packer, Terraform, letsencrypt/certbot, restic, consul
Script, programming and markup languages Kotlin, Python, Go, Java, C#, HTML, Typescript, Javascript, Dart, CSS3, Groovy, C, C++, Visual Basic, SQL, Unix Shellprogrammierung, Perl, PHP, JSP, Struts, JSF, JSON, YAML, XML/DTD/XMLSchema, XSLT, AJAX
Management skills CEO in an IT startup, IT coaching and consulting, training courses for software developers and end-users, several years of IT project management (team sizes up to 12 employees), several years of management responsibilities in an industrial environment (team sizes up to 19 employees)
Language knowledge german (native), english