Senior Fullstack Engineer (m/f/d)

🎤 Why voize? Because we’re more than just a job! At voize, we believe the greatest gift to frontline workers is time - time to care, connect, and be present. Today, that time is lost to busywork and complex systems that pull them away from what matters most: people . Our vision is to change that by building AI companions that seamlessly take over digital workflows. We don’t replace humans with technology - we amplify their impact. Our mission is backed with a $50M Series A funding led by Balderton Capital, with support from HV Capital, Y Combinator and other leading VCs. Today, 2,000+ facilities trust voize, and over 200,000 users rely on our AI companion to ease their daily workload. As a dynamic team, we combine first-in-class technology with meaningful social impact. And now, we’re looking for you to join us on this mission! 💡 Your Mission As a Senior Fullstack Engineer at voize, you will be a co-owner of voize's ML App — the in-house platform for annotation, data exploration, ML training orchestration, model evaluation, and the HIPAA-bearing data flows that move PHI from customer to model. Make in-house tooling good enough that revisiting Labelbox/Encord-style vendors is permanently off the table, and unblock HIPAA-compliant training on US customer data. 🚀 Your Daily Business - No two days are alike Co-own the ML App codebase (React/TS SPA + Kotlin services + Kotlin ETL on EKS) Design and ship features for data labelling, data exploration, ML training orchestration, model evaluation, model playgrounds, and ML-issue triage Drive the next iteration of in-house annotation tooling — UX, throughput, task-type extensibility — to the bar where vendor revisits are unnecessary Maintain CI/CD, EKS deploys, and LGTM-stack observability for ML App; triage and fix defects Pair with the Platform team on platform-side prerequisites (FGA proxy, OIDC) that the new training flows depend on Mentor and code-review across ML App; share conventions with adjacent teams (Mgmt App, Data, Platform) 🤝 Your Skillset - What you bring to the table 5+ years building production fullstack web apps with React + TypeScript SPAs Strong Kotlin (or JVM) backend experience — services, ETL/data pipelines, schema design Demonstrated ownership of a complex, production-critical system as a senior peer (not solo) Comfortable engineering with regulated / sensitive data (HIPAA, GDPR, BAA, PHI, or similar) Strong product / UX instincts (annotation, labeling, data exploration, ops UI) German proficiency at B2 level or above, and fluent in English 🌱 Growing together - what you can expect at voize We are a fast-growing startup, that means you will tackle challenges, grow quickly, and make a real impact, giving frontline workers more time for people We foster an open, collaborative culture with regular team events, whether you work from our Berlin office or remotely across Germany Become a co-creator of our success with stock options Generous perks: 30 vacation days plus your birthday of