Lead Backend Engineer

Location: Berlin, Germany (hybrid - open to exceptional remote candidates)

The platform is live and the foundation is solid - your job is not to start from scratch, but to take what exists and scale it toward a broad, ambitious vision. You will have real room to put your stamp on where the architecture and product are heading. Specifically, you will:

• Architect and own distributed backend services that operate at enterprise scale.
• Build stream processing pipelines and event-driven architectures for high-throughput data flows.
• Design performant data retrieval and storage layers optimized for low-latency access patterns.
• Integrate with LLM providers, ensuring reliable and cost-efficient inference at scale.
• Collaborate with our infrastructure engineer to evolve CI/CD pipelines, cloud infrastructure, and operational practices.
• Drive monitoring and observability standards that give the team confidence in every deployment.

You won't just write code that works - you will reason about how every component affects overall system performance, reliability, and cost. You will work alongside our AI scientists to bring state-of-the-art models into a production environment that demands low latency and high throughput. You will do all of this as part of a small, senior team at a founding stage - with a working product as your starting point and a broad vision that gives you real ownership over what comes next.

Do you have experience in Python?, Do you have a Master's degree?, * You have built and operated distributed systems in production - not just designed them on a whiteboard.

• You think in terms of system-level performance: latency budgets, throughput limits, failure modes, and the trade-offs between them.
• You have deep experience with stream processing, event-driven architectures, or real-time data pipelines.
• You are proficient in Go,Python, Java, or a comparable backend language and have strong opinions on when to use what.
• You have extensive hands-on experience with cloud infrastructure (AWS or similar) and DevOps practices including CI/CD and Infrastructure as Code.
• You work independently. You don't wait to be told what to build - you identify the highest-leverage problem and go solve it.
• You take full ownership from design through deployment through on-call.
• Bonus if you have worked on ML engineering (model serving, feature stores, ML pipelines) or data engineering (streaming ETL, data modeling, analytics infrastructure).

• The rare opportunity to join an elite team of experienced builders and entrepreneurs who have done this before - founded, scaled, and sold an AI-driven SaaS business.
• Ownership of core platform architecture and the autonomy to make the technical calls that matter.
• A fast-paced, low-bureaucracy engineering culture where shipping quality code is the only thing that counts.
• An AI-native environment with the tools and compute to stay at the cutting edge.
• A growing engineering team - you will have real leverage, not carry the whole platform alone.
• A competitive salary and a meaningful equity stake - early enough to shape the company's direction, de-risked by paying customers and strong market traction.

Current CRM marketing is broken. It blasts generic messages at scale and calls it "personalization." Our founders lived this problem while leading global, tech-enabled B2C businesses - and decided to fix it. Zelara is the AI operating system for personalized, digital customer experiences. Our platform uses generative AI and machine learning to build a self-optimizing system that personalizes every B2C interaction in real time - turning impersonal marketing into conversations customers actually welcome. Early results with enterprise customers show up to a 23% lift in conversion rates and up to 37% in revenue growth. We are well-funded, already generating revenue with paying enterprise customers, and seeing strong market pull. Now we are building the team to scale.