Senior Infrastructure Engineer

Job Description: Senior Infrastructure Engineer

Role overview

The Senior Infrastructure Engineer builds and runs the backend core that connects the companies’ 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.

Ownership: The role owns the control API, the data contracts between apps, backend and locker controllers, and the customer integrations. Owning means being accountable for their design, quality, reliability and documentation, and being the escalation point for integration and backend design issues. During incidents, Service Support restores service; this role takes over when the fix needs a change to an integration, a data contract or the backend design. The role works closely with the Lead Developer, who owns the wider codebase and overall technical direction, and shares knowledge of these areas so others in the team can cover them.

Key duties

• 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 the integrations with major logistics and retail customers, from API design and onboarding to monitoring, and act as the escalation point for 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 to chain workflows.

• Keep the backend reliable as volumes grow, through monitoring and 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, so others in the team can support and cover these areas.

Qualifications and experience

• 6+ years building backend services in Node.js/TypeScript.

• Solid REST API design, and fluency with JSON, HTTP and tools such as curl and Postman.

• Experience building and running integrations with external partners or customers.

• Hands-on Firebase experience: Firestore data modelling, security rules and Cloud Functions / Cloud Run functions.

• Experience with event-driven systems: triggers, Pub/Sub or message queues, retries and idempotency.

• A track record of running production systems at scale, including monitoring, performance and incident response.

• Comfortable on Google Cloud: IAM, Cloud Logging, Eventarc, the gcloud CLI, Cloud SQL, Memorystore and Pub/Sub.

• Sound Git habits and experience shipping to production.

• Clear written communication in English.

Nice to have

• IoT or embedded experience, such as talking to controllers over serial, MQTT, Modbus or similar.

• Experience with smart lockers, vending, access control or logistics and last-mile delivery systems.

• Docker, CI/CD and infrastructure as code.

• Mobile or web front-end experience (React).

Key attributes

• Takes ownership of systems from design through to production.

• Shares knowledge openly and documents clearly, so others can cover and build on the work.

• Works well in a small, international team.