Senior Software Engineer - Pos Integrations

ON; Greater London; On-site; GBP 90,000 - 140,000; Full time

Job summary

On is seeking a Lead Backend Engineer to drive the integration of our POS ecosystem with ERP, OMS, CRM, and loyalty engines. You will architect resilient services, design event-driven data flows, and ensure store operations remain fast, reliable.

You have deep experience with Node.js/TypeScript, APIs (REST/GraphQL), and cloud-native architectures. You will collaborate across teams to ship scalable integrations that power a unified omnichannel experience.

Qualifications

• Strong backend engineering experience with modern technologies (Node.js, TypeScript).
• Proven track record integrating APIs across commerce, ERP, OMS, or CRM domains.
• Familiar with headless commerce, microservices, and composable architecture principles.

Responsibilities

• Design, build, and scale backend services powering 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.
• Collaborate with frontend, product, and vendor teams to align integration design with platform capabilities.

Skills

Node.js

TypeScript

REST APIs

GraphQL

Kafka

RabbitMQ

OAuth

AWS

PostgreSQL

Terraform

Tools

NewRelic

Job description

In Short:

At On, retail isn't just a channel-it's an experience. As we scale our global footprint, we're laying the foundation for a future-ready Point of Sale (POS) ecosystem. To do that, we need robust backend systems that orchestrate flawless integration between the physical and digital, the store and the cloud.

We're looking for a Lead Backend Engineer to drive the integration of our POS platform with mission-critical systems like ERP, OMS, CRM, and loyalty engines. You'll architect and build resilient services, shape our event-driven data flows, and ensure our store operations stay fast, reliable, and future-proof. You'll be joining the Retail Experience team-where technology meets the shop floor and every request matters. If you love crafting clean APIs, streamlining integrations, and optimizing real-world system performance, you'll feel right at home.

Your Mission:

• Backend & Integration Engineering: 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
• Architecture & Resilience: 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
• Collaboration & Strategy: 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:

• Strong 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.

Your 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.