Senior FS (React, Node, AI) Developer

A German-based SaaS provider is digitalizing daily operations for personnel and building service providers across Europe. The company delivers end-to-end solutions to streamline processes such as recruitment, time tracking, payroll, invoicing, and reporting. Its mission is to enhance efficiency, save time, and reduce costs through comprehensive digitalization, supporting both personnel services and the cleaning service industry with specialized software.

They are developing an innovative cloud-based platform that automates timesheet digitization using cutting-edge OCR and AI vision models, validating outputs against ERP data to ensure accuracy and efficiency. The solution can operate as a standalone service or be integrated into internal ERP systems.

The company is seeking a passionate Senior Full-Stack (Next + Nest + AI) Developer who thrives in an end-to-end product environment - from robust backend APIs to intuitive frontends - with a strong focus on backend architecture and cloud infrastructure.

As an Engineer, you will develop innovative AI solutions in close collaboration with product managers, other engineers, and the Head of AI. Your goal will be to leverage the latest AI tools, frameworks, and models to solve real business problems, from rapid prototypes to scalable production systems. You will have the freedom to experiment and the responsibility to build fast, efficient systems that deliver real value and actively shape the company's AI landscape.

Duration: 2 months, with the possibility of extension. The client also has multiple projects, so they try to keep good engineers even if the project changes.

Key Responsibilities:

Ideation & Prototyping:

• Development of functional prototypes in the shortest possible time (e.g., within a week) to make the AI added value tangible
• Setting up the technical environment, including data, functional, and technical requirements
• Evaluation of use cases about technical feasibility and definition of PoCs
• Setting Goals for Initial User Testing

MVP Development:

• Implementation of AI solutions in close cooperation with PMs and business stakeholders in agile sprints
• Apply best practices for deployment, data handling, and integration
• Creative exploration of new technical approaches to solving business problems
• Development of multi-agent systems to automate entire business processes
• Integration into existing ERP systems (e.g., via MCP)
• Develop user-friendly UIs that create real customer value

Production & Maintenance

• Building test frameworks (e.g., LLM, validating, LLM) for continuous improvement
• Monitoring of performance, costs, and hallucinations to optimize the systems
• Scaling existing services across geographies and ERP systems
• Ensure stability, security, and scalability on the fly

Requirements:

• 5+ years of experience in software development, including both frontend and backend
• Deep expertise in TypeScript across the full stack.
• Proficient in multiple programming languages, including Node, TypeScript, and Python (experience with additional languages is a plus).
• Advanced AI tooling experience for productivity, including MCP, agent skills, and harness engineering with tools such as Claude Code, Cursor, Codex, and Worktrees, delivering at 10x the speed of traditional engineering.
• Hands-on experience with cloud frameworks and DevOps tools, including AWS, Docker, Kubernetes, and CI/CD pipelines.
• Proven ability to deploy productive systems and design scalable, maintainable architectures.
• Knowledge of machine learning, LLMs, and generative AI, including integrating them into production systems.
• Practical experience with modern AI tools, such as Cursor, GitHub Copilot, Lovable, or similar platforms.
• Strong understanding of API design, data pipelines, and system integrations.
• Thrive in fast-paced, exploratory, and agile environments.
• Self-driven with a sense of ownership, and able to communicate effectively within cross-functional teams.
• Fluent in English.

Why Join Us?

• An exploratory environment where you can try out new technologies and quickly translate them into functional solutions
• Production mindset: We don't just build prototypes, but real systems that have an impact on our customers' everyday lives
• The ability to independently design, standardize, and build structures for AI deployment and scaling
• Working in a highly motivated, fast-moving team with plenty of room for innovation
• Personal development in a technical or business direction
• Remote work & flexible working models