Dennis began his software engineering career while still a student, working with diverse tech stacks such as PHP, Laravel, JavaScript, Angular, and React. He later joined codecentric as a consultant and developed accreditation software for Mojo Concerts, utilizing a serverless architecture on GCP integrated with AWS services.
Following this, Dennis worked with various clients, focusing on Angular and Java on the AWS cloud platform. At Alphabet Lease, he led a team of 10 frontend engineers, made key architectural decisions including the introduction of a monorepo for frontend applications, and chaired weekly frontend meetings.