Backend Engineer – POS Platforms Integration

ON.com; Greater London; On-site; GBP 50,000 - 70,000; Full time

Job summary

ON.com is seeking a backend engineer to design and scale backend services powering integrations across various platforms. With over 3 years of modern technology experience, you will develop APIs and contribute to a cloud-native architecture that supports global retail operations.

This role involves working closely with the Retail Experience team and requires knowledge of Node.js, integration skills, and a passion for innovative solutions. Join ON to redefine retail technology!

Qualifications

• 3+ years of backend engineering experience with modern technologies (Node.js, TypeScript, or similar).
• Proven track record integrating APIs across commerce, ERP, OMS, or CRM domains.
• Solid understanding of databases and infrastructure-as-code tools.

Responsibilities

• Design, build, and scale backend services that power POS integrations.
• Develop REST and GraphQL APIs that are performant, secure, and easy to consume.
• Contribute to the design of a cloud-native architecture for global retail operations.

Skills

Backend engineering experience

API integration skills

Knowledge of message brokers

Debugging and telemetry skills

Tools

Node.js

PostgreSQL

Terraform

Job description

Your Mission

• Design, build, and scale backend services that power POS integrations across ERP, eCom, CRM, inventory, and loyalty platforms
• Develop REST and GraphQL APIs that are performant, secure, and easy to consume
• Implement real‑time and batch data sync, authentication flows (OAuth, SSO), and secure event pipelines
• Contribute to the design of a cloud‑native, event‑driven architecture for global retail operations
• Build scalable integration patterns using message queues (Kafka, RabbitMQ) and serverless workflows
• Support observability through proactive monitoring, alerting, and performance tuning (e.g., NewRelic)
• Testing & Quality Automation: ensure reliability through a robust automated testing stack—contract tests, load tests, and test data pipelines
• Collaborate with QA and DevOps to streamline CI/CD and improve release confidence
• Participate in incident response and post‑mortem analysis to continuously harden platform stability
• Partner with frontend, product, and vendor teams to align integration design with platform capabilities
• Influence technical decisions during vendor evaluations and rollout phases
• Impact roadmap decisions by sharing technical insights and platform implications
• Actively contribute to the broader architecture vision for On’s composable commerce technology stack

Your story

• 3+ years of backend engineering experience with modern technologies (Node.js, TypeScript, or similar)
• Proven track record integrating APIs across commerce, ERP, OMS, or CRM domains
• Familiar with headless commerce, microservices, and composable architecture principles
• Experience with message brokers (Kafka) and asynchronous data processing
• Solid understanding of databases (e.g., PostgreSQL) and infrastructure‑as‑code tools (Terraform)
• Skilled in designing, scaling, and monitoring cloud‑native services (AWS, GCP, or Azure)
• Familiarity with OAuth2, token‑based authentication, and secure service design
• Strong debugging and telemetry skills: logs, traces, metrics, and real‑time alerting

About the Team

At On, we don’t just create tools—we craft experiences that move the world. As part of our Retail Experience team, you’ll help build the future of in‑store technology. Your code will connect people with performance, power a seamless omnichannel journey, and support a mission that’s bigger than any one screen: to ignite the human spirit through movement. Ready to help us redefine retail? Lace up. Let’s go.

On is an Equal Opportunity Employer. We are committed to creating a work environment that is fair and inclusive, where all decisions related to recruitment, advancement, and retention are free of discrimination.