Join the AI Platform team as we build the backbone of Flo’s personalization.

We are looking for an Backend Engineer to own the User Profile service—a high-scale system (20k RPS, <15ms latency) that powers experimentation and AI for 80M+ users. In this role, you will drive the development of User Profile 2.0, bridging the gap between raw user data and advanced ML feature stores.

You will operate in a hybrid model: building core capabilities for AI/ML data representations while governing an inner-source ecosystem that allows other teams to contribute safely. If you are passionate about high-concurrency systems and enabling AI at scale, we want to hear from you!

What you'll be doing:

• Develop new features for the User Profile service – the central platform that powers personalization, experimentation, and AI features including Flo Conversational AI
• Build User Profile 2.0 capabilities including historical data arrays, AI-ready attribute representations, and integration with ML feature stores
• Design and implement data pipelines that deliver user attributes to AI/ML systems for personalized content generation and predictive models
• Enable inner-source contributions: establish contribution guidelines, quality gates, and architectural standards for product teams
• Review and approve pull requests from contributing teams, providing mentorship and ensuring code quality
• Maintain architectural oversight of core components while enabling safe, autonomous contributions from product teams
• Build and maintain attribute governance frameworks, cataloguing systems, and documentation standards
• Ensure compliance with healthcare regulations (HIPAA, SOC 2, GDPR) and implement privacy-first design patterns
• Participate in on-call rotation and drive incident response for this critical platform service
• Work in a cross-functional setup alongside other engineering teams (Backend, ML, QA), product, and analytics teams

Your Experience

Must have:

• 7+ years of professional experience building distributed backend systems at scale
• Fluency in Scala, Java, or Python – with willingness to work primarily in Scala (we'll support your ramp-up if needed)
• Deep experience with AWS services, particularly DynamoDB, EKS, and serverless architectures
• Strong understanding of observability – logging, metrics, tracing, and alerting – and how to use it to drive operational excellence
• Experience building high-throughput, low-latency APIs serving millions of users
• Solid understanding of databases (SQL and NoSQL) and experience designing APIs that prioritise reliability and performance
• Experience with code review, mentorship, and establishing engineering standards across teams
• Track record of writing clean, documented, version-controlled code
• Ownership mentality – you take initiative, don't wait to be told, and see problems through to resolution
• Strong communication skills – you can collaborate effectively with multiple teams and explain technical decisions clearly

Nice to Have

• Experience with ML infrastructure, feature stores, or data platforms that serve AI/ML workloads
• Familiarity with data pipelines and integration patterns for machine learning systems
• Experience with inner-source or open-source contribution models and governance
• Experience with platform/infrastructure teams supporting multiple product teams
• Healthcare compliance framework experience (HIPAA, SOC 2, GDPR)
• Feature flagging, A/B testing, or experimentation platform experience
• Experience in the MedTech or HealthTech domain
• Experience at a Tier-1 product company or related experience working within a product organisation