Senior Full Stack Engineer (f/m/d)

Senior Full Stack Engineer With Deep AI Experience

Kyan Health is building the most advanced AI-augmented mental health and wellbeing platform in Europe. Our mission is to bring high-quality, clinically-grounded psychological support to employees and families across multiple countries, languages, and cultural contexts — with AI playing a central role.

We are looking for a Senior Full Stack Engineer with deep AI experience , particularly in:

1. AI agents & multi-step reasoning systems

2. LLM application architectures

3. Tool-calling, retrieval, orchestration, and evaluation

4. Modern AI toolchains and best practices

You will work closely with engineering, data, product, and clinical teams to build our AI features end-to-end and help shape the future of our platform.

This is a role with massive influence — we're early enough that your architectural choices, code, and AI expertise will have a lasting impact.

Our stack

(You don't need all of this, but strong React/TypeScript + AI foundations are essential.)

Frontend

• TypeScript

• React + Next.js

• React Native (plus React Native Web)

• Component libraries/design system

Backend & Data

• Node.js (TypeScript)

• Event-driven and service-oriented architecture

• BigQuery, PostgreSQL, NoSQL stores

• Vector databases, retrieval pipelines

• Cloud infra (GCP/Azure)

AI Tooling & Ecosystem

• OpenAI API & Assistants

• Azure OpenAI (GPT, embeddings, structured outputs)

• LangChain, LlamaIndex, OpenAI function calling

• Agent frameworks (custom, or e.g. LangGraph-style)

• Evaluation suites, guardrails, prompt tooling

• Monitoring + model observability

What You'll do:

AI Architecture & Agentic Systems

• Design and implement coding agents, task-specific AI agents , and multi-step workflows that power user-facing features.

• Build and refine retrieval pipelines , embeddings flows, and hybrid RAG/logic systems.

• Architect robust prompting, function-calling, and tool orchestration systems.

Full Stack Product Development

• Own features across Next.js , backend services, and mobile/web.

• Translate product and clinical requirements into AI-powered user experiences.

• Work with data pipelines, BigQuery, analytics, and experimentation frameworks.

Cross-platform UI Systems

• Build and evolve our shared React/React Native component library and design system.

• Ensure accessibility, performance, and multi-market language support.

Technical Leadership

• Set coding standards for AI-integrated features.

• Mentor others on AI architecture, LLM patterns, evaluation, and failures modes.

• Challenge assumptions, propose better approaches, and push for pragmatic, responsible AI usage.

Who We're Looking For

Required:

• Senior-level engineering experience , ideally 6+ years, with strong autonomy.

• Deep understanding of the modern LLM ecosystem : models, embeddings, fine-tuning, structured outputs, evaluation, latency/cost tradeoffs.

• Hands-on experience building production AI agents (e.g., planning/multi-step systems, tool-calling, retrieval-integrated workflows).

• Strong React + Next.js + TypeScript experience.

• Experience building cloud-hosted applications (Azure, GCP, etc.).

• Solid backend experience with Node.js, APIs, data modeling, auth, performance.

• Familiarity with BigQuery or similar analytical data warehouses.

• Strong product awareness — focus on usability, clarity, and delivering outcomes.

• Pragmatic engineering mindset: readable code, clear patterns, low complexity.

Nice to Have:

• Prior work in healthtech , HR tech, or other sensitive domains.

• Experience with evaluation frameworks , AI observability, or human-in-the-loop workflows.

• Background in mobile development (React Native, native iOS/Android).

• Experience with multi-language or multi-market products.

Why Join Us

Make an Impact: Your work will directly contribute to improving mental health in workplaces around the world.

Ownership: You'll have the chance to take ownership of our content production processes

Innovative Environment: Work in a greenfield space where your ideas aren't just welcome—they're essential.

Collaborative Team: Join a supportive team where collaboration and innovation are at the heart of what we do. We are an easy to work with & low ego team, and want to keep it like that.

What's In It For You

• Full Access to Our Comprehensive Mental Health App:

  • Unlimited use of Kyan Health's AI well-being companion "KAI" and guided meditation courses.

  • Unlimited sessions with licensed psychologists.

  • Unlimited sessions with ICF-certified coaches.

• Competitive compensation , adjusted for experience.

• Meaningful stock options in a rapidly growing AI-driven healthtech company.

• Work with a mission-driven team and product that genuinely helps people.

• Hybrid in Berlin or remote within CET±4.

• Autonomy, ownership, and a chance to shape foundational AI systems from the ground up.

Interview Process:

• CV Check

• Get to know Kyan, Girish (30 minutes Call)

• Get to know your manager, Nacho (45 minutes Call)

• Team Interview(s), ( 30 minutes each call)

• Online or Onsite Live Coding Exercise (Nacho/Team, 120 minutes)

• Offer Stage: Meet the founder(s) (30 minutes) / Reference check / Offer