Senior Fullstack Engineer (m/f/d) - AI Health tech

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.

💡 Your Mission

As a Senior Fullstack Engineer - Freelance 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

🤝 Your Skillset - What you bring to the table

• 5+ years building production fullstack web apps with React + TypeScript
• Excellent Kotlin (or JVM) backend experience - services, ETL/data pipelines, schema design
• Demonstrated ownership of a complex, production-critical system
• Comfortable engineering with regulated / sensitive data (HIPAA, GDPR, BAA, PHI, or similar)
• Strong product / UX instincts (annotation, labeling, data exploration, ops UI)

🌱 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 off, Germany Transport Ticket, Urban Sports Club, regular company off-sites, and access to learning platforms such as Blinkist and Audible, plus free language courses
• You decide when you work best, that means flexible working hours and a good hybrid set-up.