Senior Backend Engineer

BlackMountain is a technology company based in Vienna and Munich. We are developing a European human-centric intelligence platform that orchestrates internal company knowledge, external market signals and AI tools. Our aim is to enable leadership teams to make informed decisions that align economic and ethical objectives. We are a small, closely collaborating team where responsibility is shared across disciplines. We value the ability to learn and adapt – regardless of discipline or title. BlackMountain is a place for people who want to contribute to responsible technology development with a positive societal and environmental impact. Tasks Backend Architecture & Development: Design, build, and operate scalable backend systems and APIs. You own the backend architecture from database to API layer and ensure performance, reliability, security, and maintainability across distributed systems. You design modular systems following SOLID principles, implement RESTful APIs with clear contracts, and build background job processing for asynchronous workloads. Data Layer & Performance: Design and maintain efficient database schemas, migrations, and versioning strategies. You ensure data integrity through constraints and transactions, optimize queries and indexes, and design multi-database architectures where required. Security & Reliability: Implement secure authentication and authorization, manage secrets and sensitive configuration, and protect backend systems against common vulnerabilities. You design for fault tolerance, rate limiting, abuse prevention, and reliable operation in production. Integrations & External Services: Integrate backend systems with third-party services such as payments, email, and storage. You build webhook handlers, event-driven integrations, resilient external API consumption patterns, and provide health checks and monitoring endpoints. Quality, Operations & Collaboration: Write automated tests at multiple levels, participate in code reviews and architectural decisions, document systems and runbooks, monitor system health and performance, and support production systems and incident response. Requirements Core experiences 5+ years backend development experience 3+ years TypeScript in production environments 2+ years with modern Node.js frameworks (NestJS, Nextjs) Strong SQL and NoSQL database experience Authentication/authorization system implementation Message queue and async processing experience RESTful API design and documentation Additional strengths Multi-database architecture experience Payment system integration (Stripe, PayPal) Observability and monitoring implementation (OpenTelemetry, Datadog) Microservices or distributed systems experience Open-source contributions Technical leadership or mentoring experience Benefits At BlackMountain, we believe that good work emerges where people are trusted, supported, and given room to grow. We aim to foster a culture of trust, responsibility, and shared excellence — where people can work with clarity, autonomy, and a sense of purpose. We offer flexible working models that acknowledge different life situations. You can work from our office in Vienna or Munich. Flexible working hours and home office options allow you to structure your work in a way that supports focus, balance, and long-term sustainability. To support your professional development, we invest in learning and growth. You will have access to professional training and mentoring by our experienced consultants, creating space for skill development and long-term perspective. We value plural perspectives and understand them as drivers of innovation. Therefore, we aim to diversify our team not only in terms of professional expertise, but also across socio-demographic diversity dimensions. To support this goal, we actively encourage applications from individuals who are underrepresented or face disadvantage on the basis of gender, sexual identity, disability, religion, or origin. Where qualifications are equal, we give preference to candidates from these groups. For your day-to-day work, we provide a company laptop. Full-time employment is based on 38.5 hours per week, with compensation according to the Austrian collective agreement and the possibility of overpayment depending on qualifications and experience. Show us who you are — in your own way. You can send a written application, a presentation, work samples, or anything else that tells us: what you care about, what skills you bring to the team, what you’d like to learn, and why BlackMountain feels like the right place for it. Include motivational letter, portfolio, GitHub or case study if helpful. We value individuality more than form. Find Jobs in Germany on Arbeitnow