Senior Infrastructure Engineer

About the role

The Senior Infrastructure Engineer builds and runs the backend core that connects the company's apps, its major logistics and retail customers and its parcel lockers. The role is as much about keeping the backend reliable and performant at scale as it is about building features. It owns the control API, the data contracts between apps, the backend and locker controllers and the customer integrations, and acts as the escalation point for integration and backend design issues. During incidents, Service Support restores service; this role takes over when the fix requires a change to an integration, a data contract or the backend design. The role works closely with the Lead Developer and shares knowledge so others in the team can cover these areas.

Key responsibilities

• Build and maintain the control API (Node.js/Express).
• Design the JSON contracts between apps, the backend and locker controllers, and keep them documented and versioned.
• Own integrations with major logistics and retail customers, from API design and onboarding to monitoring, and escalate integration issues that Service Support cannot resolve.
• Build event-driven backend logic on Firebase using Firestore triggers, Cloud Run, Cloud Run functions (2nd gen) and Pub/Sub.
• Keep the backend reliable as volumes grow, through monitoring, alerting, performance tuning, capacity planning and resilience patterns such as retries, rate limiting and graceful degradation.
• Migrate legacy 1st gen Cloud Functions to Cloud Run functions and v2 Firebase triggers.
• Debug issues end to end, from curl and logs to Firestore data and device behaviour.
• Write tests, review code and help set engineering practices for the team.
• Share knowledge through documentation, runbooks, pairing and handovers.

Required profile

• 6+ years building backend services in Node.js/TypeScript.
• Experience building and running integrations with external partners or customers.
• A track record of running production systems at scale, including monitoring, performance and incident response.
• Clear written communication in English.
• Nice to have: IoT or embedded experience, smart locker or logistics experience, Docker, CI/CD and infrastructure as code, React.

Required skills

• Solid REST API design and fluency with JSON, HTTP, curl and Postman.
• Firebase: Firestore data modelling, security rules, Cloud Functions and Cloud Run functions.
• Event-driven systems: triggers, Pub/Sub, message queues, retries and idempotency.
• Google Cloud: IAM, Cloud Logging, Eventarc, gcloud CLI, Cloud SQL, Memorystore and Pub/Sub.
• Sound Git habits and experience shipping to production.