Senior Software Engineer - Python/AWS

Senior Engineer (IC3)

Full-time: Hybrid

Location: London

£80,000 - £100,000 per annum D.O.E

Team: Backend (platform) Team - Python-focused Stack

As a Senior Engineer (IC3) at Lunio, you lead the design and delivery of complex, cross-service features on our ad-fraud prevention platform. You set a high bar for engineering quality by example. You make pragmatic architectural choices and help others navigate ambiguity. You operate the services you build, improve reliability and performance, and mentor teammates so the whole squad ships value predictably. You implement and deliver working solutions on an ongoing basis.

Key Responsibilities

Lead complex delivery: shape scope and architecture for cross-service features/platform work, break down ambiguity, coordinate across Product/Design/Data to land outcomes.

Raise the quality bar: define practical standards for testing, security, and observability, act as approver on critical PRs, model excellent reviews and pairing.

Operate and improve production: own service performance targets for your area, lead incident response, drive corrective actions to completion, and reduce recurrence.

Grow others: mentor and unblock teammates, transfer knowledge through pairing, docs, and structured feedback.

Shape team practices & roadmap: contribute to technical strategy and sequencing, surface trade-offs and risks early, champion incremental delivery.

Service Ownership: own the full software development lifecycle not only for your changes, but for all changes that affect a Service you have worked on, by monitoring PRs and success metrics for your services

What makes a great Senior Engineer at Lunio?

Software Design & Architecture: Designs evolvable systems with clear boundaries and data ownership, anticipates failure modes and keeps solutions simple.

Technical Execution & Delivery: Leads execution across multiple stories/engineers, breaks down ambiguous problems, and delivers predictably with sensible trade-offs.

Testing, Reliability & Observability: Bakes in testability, defines/uses service performance targets, alerts, logs, and traces, advocates for reliability alongside features.

Security & Privacy: Applies secure-by-default patterns, reviews dependencies/risks, and addresses vulnerabilities within the team’s domain.

Collaboration & Communication: Facilitates decisions, aligns stakeholders, and records them via concise docs others can follow.