[Remote] (Senior) Full-Stack Software Engineer - Financial Infrastructure & Payments (m/f/d)

Note: The job is a remote job and is open to candidates in USA. 1KOMMA5° is a CleanTech Unicorn on a mission to electrify everything and connect everyone to the future energy market through their AI-based software platform, Heartbeat AI. They are seeking a Senior Full-Stack Software Engineer to design and run billing, invoicing, and monetization systems that support the global energy transition, ensuring scalability, reliability, and performance while collaborating with various teams.

Responsibilities

• Contribute as a Full-stack engineer within a team of self-driven software developers
• Design, build, and maintain business-critical systems across the stack. From scalable backend services and APIs to performant, user-friendly frontends with reliable flows for invoices, payments, and subscriptions where they touch customers and finance
• Partner with finance, operations, and product to translate complex, loosely defined billing requirements into clear, actionable technical solutions, including compliance-minded documents and audit-friendly reporting where needed
• Own slices of the invoice lifecycle (generation, delivery, and archival), templating and localization, and reconciliation and reporting together with stakeholders
• Champion clean architecture, component reusability, and maintainable UI patterns using modern frameworks (e.g. React, Next.js, or similar)
• Drive experiment-driven innovation and uphold strong engineering practices in testing, CI/CD, observability, and code quality
• Continuously improve developer experience by reducing technical debt, automating workflows, and documenting key decisions and operational processes
• Operate effectively in an asynchronous, outcome-oriented environment, managing your work autonomously and maintaining clear communication through documentation and structured updates
• Contribute to lightweight project management by defining milestones, ensuring technical feasibility, and aligning engineering work with product goals

Skills

• Experience writing maintainable, reusable, and testable code in TypeScript, with strong skills in both frontend frameworks and backend technologies
• Strong understanding of API design, data modeling, and system integration (RESTful or GraphQL), including patterns for idempotent money movement and auditable billing events where relevant
• Proven ability to own features end-to-end, from UX and architecture to deployment and monitoring
• A pragmatic, product-focused mindset that balances technical excellence with delivering customer value for regulated or finance-adjacent flows
• Curiosity and initiative to explore new tools and methods that improve product quality and engineering efficiency
• Excellent written and spoken English (German is a plus)
• Residency in Germany

Benefits

• You are part of an international, dynamic, and highly motivated team of people who have proven to make things happen
• With your work, you accelerate the "energy transition" and hence have a direct impact on our climate
• Work with and learn from other super-smart colleagues
• You will enjoy direct contact with core decision-makers
• You will enjoy entering full-time in one of Europe’s most thriving scaleups
• You work remotely (Germany-wide), with offices in Hamburg, Berlin or Munich
• Create a healthy balance alongside your work and enjoy all the benefits of the EGYM Wellpass
• Benefits and discounts are yours with Futurebens
• Whether city bike or e-bike - be flexible with our job bike leasing and do something good for the environment at the same time

Company Overview