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

voize; Deutschland; Remote; EUR 90,000 - 130,000; Part time

Benefits offered by this job

30 vacation days plus your birthday

Germany Transport Ticket

Urban Sports Club

stock options

regular company off-sites

learning platforms like Blinkist and A

Job summary

voize, a Berlin-based startup, is seeking a Senior Fullstack Engineer - Freelance to co-own our ML App, an in-house platform for data labeling, ML training orchestration, and HIPAA-bearing data flows from customers to models.

You will work on a React/TypeScript frontend and Kotlin backend on EKS, shaping UX and data pipelines while maintaining CI/CD, security and observability. Remote across Germany with flexible hours and stock options.

Qualifications

• 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)

Responsibilities

• 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

Skills

React + TypeScript

Kotlin backend

Ownership

HIPAA/GDPR

UX instincts

Tools

Kubernetes

CI/CD

Job description

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 - 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
• access to learning platforms such as Blinkist and Audible
• free language courses
• flexible working hours
• good hybrid set-up