Tristan Zellner

Founder & Managing Director

All-in-one platform for professional group travel operators – accommodation, bookings, participants and invoices in one place.

• Fullstack Ruby on Rails application for managing group travel
• Independent conception, design, process development and implementation
• Customer workshops and requirements analysis for customisation and further development
• AI-assisted development with Claude Code and Cursor
• CI/CD, operations, backup and maintenance

CTO / Head of Software Development

Leading software development as technical and strategic sparring partner to executive management.

• Strategic alignment of technologies, personnel and processes
• Building an internal development team – hiring, onboarding, internal structures
• Managing external service providers including quality management and crisis intervention
• Personnel responsibility for up to 15 people – 1:1s, development, salaries
• Acquisition and sales meetings as technical contact

Software Engineer

Full-stack development and technical product owner for several banking and finance products.

• Development of digital application processes for banking products
• Technical Product Owner – interface between business and development
• REST API development for a financial analysis product using Ruby on Rails
• Refactoring a fullstack Rails application into an SPA/API architecture (Rails + React + React Native)
• Leading a team of up to 15 developers on a multi-tenant SaaS application
• Modularisation and refactoring of legacy code

Founding and development of travelbuddy

• Complete conception and new development of software for managing group travel for SMEs
• Development of processes and design
• AI-assisted development with Claude Code and Cursor
• Deployment and operation on self-managed virtual private servers
• Coverage of the complete software development lifecycle

Leading a multi-tenant SaaS in banking

• Leading a team of up to 15 developers on a multi-tenant software-as-a-service application
• Roadmap planning and staffing capacity management
• Refactoring legacy code and modularising components to improve multi-tenant capabilities
• Participating in acquisition and sales meetings as technical contact
• Requirements and implementation management with clients

Leading an architecture refactoring project

• Refactoring a fullstack Ruby on Rails application into an SPA/API architecture (Rails backend + React frontend + React Native mobile)
• Complete planning and management of the refactoring project including active backend development

Various Ruby on Rails projects

• Backend and fullstack development for various clients and products
• Development and maintenance of REST APIs
• Integration of various external APIs and third-party services
• Test Driven Development (TDD)
• CI/CD pipelines and independent operations