Staff Software Engineer

The Interstellar Squad owns a core part of our commercial platform: the billing run — a mission-critical, high-volume pipeline that turns large-scale usage data into timely, accurate invoices for customers worldwide. It's a technically rich domain: distributed data processing, event-driven workflows, financial correctness, and operational reliability at scale.

We're looking for a Staff Software Engineer to set the technical direction for Interstellar, raise the engineering bar across the squad, and guide delivery of a platform that has to stay correct, predictable and scalable as the business grows.

A central part of this role is leading the gradual modernisation of a mature platform into a set of focused, TypeScript-based domain services — using a strangler-fig approach to extract capabilities incrementally, keeping the existing system safe and our customers unaffected while we evolve the architecture.

You'll report to an Engineering Manager and partner closely with the Product Manager, Delivery Manager and engineers in the squad, as well as peer Leads across the domain. You'll have the mandate to shape how we design, build and run our systems — and the responsibility to keep the team aligned behind that direction.

This role is based in the UK to work alongside the local squad and a team in Poland. You will be expected to travel to our Poland offices at least once a quarter.

Key Responsibilities

• Set and communicate a clear technical vision for the squad's services, aligned with product and business objectives, and translate it into concrete near-term work
• Lead the incremental decomposition of a mature platform into well-bounded, TypeScript / Node domain services using a strangler-fig pattern — defining seams, sequencing extractions, and protecting delivery and correctness throughout
• Define and uphold engineering standards for code quality, testing, observability, and operational readiness across the squad — applied consistently to both legacy and new services
• Own complex technical decisions end-to-end: articulate trade-offs, choose an approach, document it, and bring the team along
• Drive architecture and system design for distributed, data-intensive billing workflows — simplifying where we can, investing where it pays off
• Lead the design and implementation of SLIs and SLOs for squad-owned services (Grafana), and take ownership of their health and reliability in production
• Guide CI/CD and delivery practices in collaboration with the squad (GitLab), keeping cycle time short and releases safe across both old and new components
• Raise the bar on code review — provide thorough, growth-focused feedback and coach engineers to do the same
• Mentor engineers at all levels, create clear growth paths and unblock them day to day; help the team build confidence in modern TypeScript/Node practices
• Champion AI-assisted/agentic engineering (IDE agents, CLI tooling, reviews) — set norms for when and how to use it, keep humans accountable for correctness, and share practices with peer squads
• Partner with Product and Delivery to shape roadmaps, size work honestly and manage technical debt with intent
• Represent the squad in cross-domain technical forums and contribute to the wider engineering direction

Key Experience & Skills

Required

• Proven experience leading the technical direction of a squad or product area, not only as an individual contributor
• Deep, production-proven backend expertise in a modern, strongly-typed stack — ideally Node.js / NestJS / TypeScript and/or PHP 8.x / Symfony
• Demonstrable experience modernising or decomposing a mature monolithic / legacy system into smaller services — comfortable with strangler-fig, anti-corruption layers, contract design, dual-write / shadow strategies, and incremental cut-overs
• Strong background in distributed systems and event-driven / asynchronous processing (e.g. RabbitMQ, Kafka, SQS)
• Experience designing and operating data-intensive, business-critical services where correctness, idempotency and recoverability matter
• Strong command of PostgreSQL (query design, indexing, performance tuning); bonus for distributed/sharded setups (e.g. Citus)
• Experience owning CI/CD pipelines and release strategy in a team setting (GitLab or equivalent)
• Track record of defining and enforcing engineering standards — type safety, clean architecture, testing, observability
• Practical experience with observability and SLO-driven operation of production services (metrics, tracing, logs; Grafana or similar)
• Strong communication and stakeholder skills: can explain trade-offs to engineers, PMs and senior leadership clearly and honestly
• Experience mentoring engineers and developing them over time
• Sensible, hands-on exposure to AI-assisted development (e.g. Cursor, Claude Code, GitHub Copilot or similar) with a thoughtful view on where it helps, where it doesn't, and how to use it safely in a team context

Preferred

• Experience leading a PHP 1 TypeScript / Node transition (or equivalent cross-language modernisation)
• Strong understanding of TypeScript at an architectural level: generics, decorators, dependency injection patterns and type system design
• Experience with PHP / Symfony monorepos and shared library patterns
• Background in billing, financial or metering/rating domains
• Familiarity with AWS-based platforms (ECS, S3, Parameter Store, SES)
• Experience evolving a team from an IT-delivery mindset toward a Product Operating Model
• Exposure to projects involving LLMs or Machine Learning in a production context