Principal Backend Engineer (Python + AWS)

Netrin is a sports technology company building products that improve fitness, lifestyle, and performance. We're now building a D2C product (pre-product stage) at the intersection of health data and AI. If you have strong Python and AWS fundamentals, enjoy owning backend systems end-to-end, and want to be one of the first engineers shaping something new this could be the perfect opportunity for you.

We're looking for a Principal Engineer architecting and building the Python backend, owning the AWS infrastructure and DevOps, and setting the engineering bar as we grow from a stealth founding team. You'll be one of the first engineers and the technical anchor for the system shaping the architecture, not inheriting it. The platform integrates LLM services, so comfort working alongside AI components is a plus, but the core of this role is rock-solid backend engineering and production infrastructure ownership.

RESPONSIBILITIES

Make and document the key technical decisions, and set conventions the team builds on

Design, build, and maintain backend APIs and services in Python (FastAPI) on AWS-based, containerised infrastructure

Own small-scale DevOps and cloud infrastructure provision and maintain compute, storage, databases, networking, and observability as code (Terraform): VPCs, ECS, S3, RDS, SQS, KMS, IAM

Build and operate asynchronous data processing pipelines (SQS-driven workers) and LLM service APIs as backend dependencies

Design and optimise vector data storage, PostgreSQL schemas for structured and semi-structured data

Implement and own CI/CD pipelines for reliable, repeatable, least-privilege deployments

Drive security and data-protection best practices encryption, logging and least-privilege IAM

Integrate authentication and authorization with strong RBAC integration

Establish testing, observability, and operational standards

MUST-HAVE REQUIREMENTS

68 years of professional backend engineering experience with Python, including a track record of owning systems end-to-end

Deep, hands-on production experience with AWS as a primary infrastructure owner ECS Fargate (and/or Lambda), S3, RDS, SQS, IAM, KMS, VPC networking

Hands-on experience with Infrastructure-as-Code (Terraform) module design, state management, and multi-environment setups

Strong PostgreSQL skills schema design, query optimisation, and operating it in production

Proven experience designing and operating scalable, fault-tolerant, asynchronous/event-driven systems

Experience building and maintaining REST APIs (FastAPI or similar)

Hands-on ownership of CI/CD pipelines and production monitoring/observability (CloudWatch, structured logging, alerting)

Experience implementing authentication and authorization (OAuth2 / JWT, role-based access control)

Strong grasp of security fundamentals encryption at rest/in transit, least-privilege access, and audit logging

Strong problem-solving ability, sound technical judgement, and clear written and verbal communication

Bachelor's degree in Computer Science, Software Engineering, or a related field or equivalent demonstrable experience

GOOD-TO-HAVE REQUIREMENTS

Experience integrating LLM APIs into production systems

Experience with Retrieval-Augmented Generation (RAG) pipelines including retrieval tuning, evaluation, and guardrails

Familiarity with vector databases / pgvector and embedding models

Experience with PostGIS or geospatial query workloads

Experience running compliance-sensitive systems health-tech, fintech, or domains with strict data-handling rules

Experience leading or mentoring engineers, and authoring architecture/decision records

Exposure to mobile-backed product surfaces

WHY JOIN NETRIN?

Be part of a new team building the future of health in stealth

Principal-level ownership set the architecture and engineering standards from day one

Work with modern cloud-native infrastructure and AI-first tooling

Small, highly efficient team with a strong culture of engineering rigor

Attractive compensation and flexible working conditions

Apply today and be part of something new! Netrin is an equal opportunity employer. We value diversity and encourage applicants from all backgrounds to apply.