Zing Coach is the world’s first AI Fitness Personal Trainer, revolutionising the way people approach health and wellness. Four years ago, we set out to replace traditional PT sessions with smart, personalised, motivating guidance powered by AI. We’re not just another app – we’re a movement, on a mission to help everyone reach their full physical and mental potential.

We are looking for a Backend Tech Lead to take technical ownership of our backend platform as it evolves from a consumer-focused product into a system that can reliably support large-scale partnerships and step-function growth. At Zing, a large part of our product is built around AI capabilities - including LLM-powered agents and computer vision. The backend plays a central role in orchestrating these components: integrating models, managing data flows and scaling AI-backed features in production.

This role is for a senior, hands-on backend engineer with strong architectural judgment. You will work on a production system in Python, help scale it for high load and reliability, and shape how we design, build, and operate backend services going forward. The role carries high technical and process authority and is deeply involved in delivery. People management is not required, but experience leading teams or squads is welcome.

Responsibilities

• Backend architecture & evolution

  • Take ownership of the current backend architecture (Python distributed monolith + services)

  • Design and operate backend services that integrate with LLMs and bespoke ML systems

  • Evolve the system to handle high load, burst traffic, and partner-driven scale

  • Design pragmatic incremental improvements that balance speed, reliability, and long-term maintainability

• Hands-on delivery

  • Write production code on critical backend paths on a weekly basis

  • Deliver both product features and technical improvements from early on

  • Own team’s changes from system design through implementation, rollout, and monitoring

• Scaling, performance, and data

  • Design and optimize systems for performance, throughput, and resilience

  • Work with relational databases (PostgreSQL preferred): schema design, query optimization, migrations, replication, and bottlenecks

• API design & system boundaries

  • Own and improve APIs between backend services, mobile applications and AI components

  • Establish clear, stable, and usable contracts that scale with product and partner needs

  • Help define how backend responsibilities are split across services as the system grows

• Reliability & observability

  • Raise the bar on logging, metrics, tracing, alerting, and operational visibility

  • Work closely with SREs and other engineers to improve reliability and incident response

  • Design systems with failure modes and recovery in mind

• Technical leadership

  • Lead architectural discussions for new features and major changes

  • Influence engineering practices: code reviews, PR flow, delivery discipline, and technical decision-making

  • Be a reference point for backend decisions without becoming a bottleneck

We expect that you have

Must-have experience

• Strong backend engineering experience with Python (Django and/or FastAPI)

• Proven experience scaling backend systems for performance, reliability, and high load

• Deep experience with relational databases (PostgreSQL preferred)

• Hands-on experience with message-based systems (e.g. RabbitMQ or similar)

• Experience running backend systems on cloud infrastructure (AWS or equivalent)

• Strong understanding of API design for backend ↔ mobile client interactions

• A clear delivery mindset: you ship, iterate, and take responsibility for outcomes

• Architectural judgment and the ability to work within real-world constraints

• Fluent English

Nice to have

• Experience in other languages like Go

• Experience designing systems for large partners or enterprise-scale usage

• Experience with CI/CD pipelines and production operations

• Experience working in fast-moving or ambiguous environments

• Interest in health, fitness, or consumer-facing products

Why working at Zing is awesome

• Be part of the fastest-growing fitness and lifestyle startup

• AI and LLMs are not only a core to our product but also is how we build software day to day

• Engineers directly impact on product and architecture decisions

• Intersection of B2C scale and large B2B for AI-driven product features

• Growth at Zing comes from taking on larger technical problems, deeper ownership, and broader influence

• Excellent work environment: the company is small enough to be person-oriented

Come be a part of something extraordinary at Zing AI Coach – where innovation meets inspiration, and every day brings new opportunities for growth and impact. Join us and help us create an exceptional user experience for Zing Coach!