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.
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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.

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.

🏆 Must-haves

• Strong experience with TypeScript.
• Professional experience developing backend services with Node.js and NestJS.
• Experience building modern frontend applications with React.
• Solid understanding of PostgreSQL and relational database design.
• Experience consuming and integrating external APIs.
• Good understanding of RESTful API design and HTTP protocols.
• Experience with Git and collaborative software development practices.
• Strong problem-solving skills and the ability to work independently.
• Excellent communication skills and the ability to work directly with both technical and non-technical stakeholders.

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🙏 Nice-to-haves**

• Experience designing and building API integrations at scale.
• Familiarity with authentication standards such as OAuth 2.0, OpenID Connect, JWT, or SAML.
• Experience with cloud platforms (AWS or GCP).
• Knowledge of Docker and containerized deployments.
• Experience with CI/CD pipelines.
• Familiarity with event-driven architectures, messaging systems, or webhooks.
• Experience working in customer-facing or implementation engineering roles.
• Experience with AspenTech tools.

☑️ Job requirements

• Availability: Full-Time Freelancer
• Remote location, preferably in the European Union
• Fluency in English

🛠️ How we work

• Asynchronous first: We minimise unnecessary meetings and document everything in Notion.
• Focus time & deep work: Meetings-free mornings + 1 in-office Team Day per week.
• Fast-paced, iterative development: We push to main frequently and release several times per week.
• Strong testing culture: Pragmatic test-driven development (TDD), heavy use of E2E tests.

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🤫 Why Join Us?**

• 🚀 Impact: Be part of a small, high-performing team driving real-world sustainability impact.
• 🔀 Hybrid work and central Munich offices: work from the office and from home.
• 📈 Growth: Join an early-stage startup with significant ownership and career growth potential.
• 🦾 Cutting-edge tech: Work on exciting challenges in automation, AI, and compliance tech.

👥 Meet the Team

Atmen was initially founded by Flore, Quentin and Erika - forming a strong and competent team bringing 15 years of working experience in the renewable energy sector and an outstanding network. Their competencies are at the crossings between data analytics, energy markets & regulation and product design.

What the team shares? A huge drive to decarbonize our industry, and a fundamental belief that a success is always a people success. An obsession to solve big problems and constantly raise the bar.

⚖️ Atmen is an equal opportunity employer

We embrace diversity **and are committed to creating an inclusive environment for all employees and stakeholders. We are open to all candidates without regard to age, color, national origin, religion, gender or any other characteristics.

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