Full-Stack Engineer – AI-Driven Development

• Co-own an area of MMT's media-planning platform, such as Media Planning, Reporting Center, Data or API
• Work end to end across backend and frontend with a small team of engineers and client relations
• Decide what gets built and how it fits together
• Turn customer needs and business outcomes into clear direction
• Look after the long-term architecture, quality and user value of the owned area
• Debug production issues and handle customer issues
• Contribute to design decisions
• Work closely with users, client relations and other teams
• Help shape engineering processes for working with AI coding agents
• Maintain team backlogs and collectively decide work priorities
• Make technical decisions based on how difficult they are to undo
• Collaborate across area teams and share knowledge
• Build and maintain software for media agencies and advertisers to plan, run and measure campaigns

• Experience building and running web applications across backend and frontend
• Ability to recognize good code, including code written by others
• Good knowledge of Ruby on Rails, Phoenix Framework, or a similar web framework
• Good knowledge of a frontend framework such as React, Vue.js, or Angular
• Good knowledge of a relational database such as PostgreSQL
• Hands-on experience with AI coding agents such as Claude Code, Codex, or Cursor
• Realistic understanding of where AI coding agents perform well and where they fail
• Clear written communication skills
• Care for testing, maintainability and architecture
• Willingness to reject changes that work but do not fit the architecture
• Ability to communicate with users and turn vague requirements into concrete acceptance criteria
• Fluency in English and/or German; English is the company language
• Work permission and residence in Germany, or willingness to relocate to Germany
• Knowledge of Elm, Elixir, or multi-tenant SaaS applications is a plus
• Experience in media or advertising is a plus

• Flexible working hours with remote work up to 100%
• Laptop running Linux or Mac
• Company-paid access to leading AI coding agents
• Subsidized ticket for public transportation (Deutschlandticket)
• Subsidized gym membership (Hansefit)
• Job bike leasing
• Company pension scheme
• Regular appraisal, feedback and development talks
• Opportunities to visit conferences, trade shows, tech-events and training options
• Time to try out new AI tools and ways of working
• Experienced colleague onboarding support
• Monthly company meetings, parties, game nights and cultural events
• Flexible working times and independent task completion
• Space and time for personal growth and learning new things