Freelance Software Engineer (Full Stack: Node.js, React, TypeScript)

🚀 About Atmen Atmen is a Munich-based RegTech startup revolutionising green certification. Our SaaS platform helps energy-intensive industries (fuels, chemicals, materials) automate compliance and certification—cutting down time by up to 90%. We replace today's manual, costly, and unpredictable certification processes with continuous, technology-driven verification. Our mission? Making sustainable production simple, scalable, and cost-effective. ** About the Role** We’re looking for a Software Engineer to help build and deliver customer-facing solutions by integrating our core platform with a wide range of third-party systems and APIs. This role combines full-stack application development with systems integration, requiring someone who enjoys solving complex technical challenges and turning customer requirements into reliable, scalable software. You’ll work closely with product managers, customer success, and engineering teams to design, develop, and deploy solutions that connect our platform with our customers’ technology ecosystems. Tasks What You’ll Do Design, build, and maintain full-stack applications using Node.js, React, TypeScript, NestJS, and PostgreSQL. Develop and maintain integrations with external APIs, including REST and other web service technologies. Extend and customize our core platform to meet customer-specific business requirements. Design clean, maintainable, and scalable backend services and frontend applications. Collaborate with customers and internal stakeholders to understand integration requirements and translate them into technical solutions. Troubleshoot integration issues across distributed systems and work with third-party vendors when necessary. Write well-tested, production-ready code with a focus on reliability, performance, and security. Participate in code reviews, architecture discussions, and continuous improvement initiatives. Contribute to documentation for integrations, APIs, and internal development processes. Requirements