Lead Backend Engineer – POS Platforms Integration

London, United KingdomOn-site

Responsibilities

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
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
Proven track record integrating APIs across commerce, ERP, OMS, or CRM domains

We’re looking for a Lead Backend Software Engineer to drive the integration of our POS platform with mission-critical systems like ERP, OMS, CRM, and loyalty engines.
experience with modern technologies (Node.js, TypeScript, or similar)
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

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:

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.
You’ll architect and build resilient services, shape our event-driven data flows, and ensure our store operations stay fast, reliable, and future-proof.
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:
Familiar with headless commerce, microservices, and composable architecture principles •
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.
Ready to help us redefine retail? Lace up. Let’s go. What We Offer