Hybrid Senior Full Stack Developer

at cosmos™

• Job title: Senior Full Stack Developer
• Job type: Full Time
• Experience level: Senior
• Salary: Not specified
• Degree requirement: Bachelor's Degree
• Tech skills: PHP, React, Symfony, TypeScript
• Location requirements: Hybrid, Darmstadt, Germany

About the role

• Senior Full Stack Developer creating infrastructure that connects business objectives and operational reality. Collaborating with a lean team to build critical product capabilities.

Responsibilities

• Build critical product capabilities with high-quality, maintainable code using our stack: Typescript, React, PHP, Symfony
• Own features end-to-end, from initial architecture and implementation through deployment, monitoring, and iteration based on customer feedback
• Guide and lead architecture decisions that balance immediate needs with long-term scalability and maintainability
• Navigate technical complexity, debug production systems, investigate performance issues, and make architectural decisions that balance speed and maintainability
• Review code, enforce best practices, and support continuous integration and automated testing across the team
• Mentor team members on AI adoption and best coding practices
• Collaborate across disciplines, working directly with product, design, and fellow engineers to ship cohesive solutions that solve real customer problems

Requirements

• 5+ years of experience as a software engineer with demonstrated technical depth
• You work independently with minimal supervision and a strong sense of impact
• You see patterns across problems and can translate technical decisions into business outcomes
• Strong debugging and investigation skills
• You elevate those around you—through thoughtful code reviews, pairing sessions, or leading by example
• You communicate and collaborate effectively in English (German is a plus but not required)
• You thrive in ambiguity, making forward progress when requirements aren't perfectly clear, and enable others to do the same
• You care about code quality but know when perfect is the enemy of shipped

Benefits

• Autonomy to shape your work, influence architecture, and own meaningful problems
• Small team where your decisions directly impact customers and product direction
• Remote flexibility or work from our office