The Role
We’re looking for a highly skilled Senior Backend Engineer who wants to do more than just write API endpoints.
At CoCoach, we are building the future of coaching and are looking for someone who combines strong backend expertise with a genuine interest in products, customers, and business impact.
We don’t believe in silos. This role combines backend engineering, product development, DevOps, data, and AI. You will work across the platform, helping to build scalable systems and meaningful product experiences while collaborating closely with both technical and commercial stakeholders.
You’ll join a small, focused team with a high degree of autonomy and responsibility, where your work will directly influence the future development of the platform.
Key Responsibilities
- Build and scale core backend functionality
- Develop APIs, integrations, and data pipelines
- Contribute to architectural and technical decisions
- Support the development of AI-powered product features
- Improve infrastructure, deployments, and developer workflows
- Ensure platform reliability, performance, and scalability
- Work closely with product and business teams to solve customer problems
Tech Stack
- Ruby on Rails
- PostgreSQL
- Redis
- REST APIs
- Background jobs
- CI/CD, observability, deployments, and cloud infrastructure (provider-agnostic)
- AI-native systems and data pipelines (LLMs, embeddings & vector search, retrieval systems, agent architectures, model providers, structured data flows, evaluation loops), plus data modeling, analytics pipelines, and event-driven architectures
About You
- Senior Expertise: You have 5+ years of experience building and scaling backend systems (ideally with Ruby on Rails).
- Data-Aware: You are comfortable working with data - modeling it, structuring it, and ensuring it flows reliably through systems and into intelligent product features.
- Product Mindset: You think in products, not just tickets. You understand the "why" behind a feature and prioritize customer impact over technical perfection.
- Infrastructure Fluency: You have a strong interest (or experience) in DevOps. You enjoy setting up pipelines and ensuring everything runs like a well-oiled machine.
- Pragmatic & Fast: You know when to build a "gold-plated" solution and when a "good enough" version is needed to validate a concept.
- AI-Forward: You have hands-on experience building with modern AI systems — or a strong, demonstrable drive to go deep. You understand LLM capabilities and limitations, think in terms of data quality and evaluation, and want to design robust AI-powered product systems, not just call APIs.
- Collaborative: You enjoy a high-energy startup environment and want to be in the office in Nordhavn most days.
What You'll Get
You will join CoCoach at an exciting stage of growth and become part of a small, ambitious team where ownership and initiative are highly valued. This is an opportunity to work in a fast-moving environment with significant learning opportunities, close collaboration, and plenty of room to make an impact.
Based in our Nordhavn office, you'll work alongside talented and driven colleagues in a culture defined by trust, energy, and low bureaucracy. We also offer free lunch, office snacks, Friday beers, and regular social events.
