Senior Software Engineer

Company Description

We're ASOS. We blend our flair for fashion with our love of cutting- edge technology, but more importantly were interested in how we can bring the best out of you.

We exist to give people the confidence to be whoever they want to be, and that goes for our people too. At ASOS, you're free to be your true self without judgment, and channel your creativity into a platform used by millions.

Job Description

Senior Software Engineer (FinOps | Digital Foundation)

We're looking for a Senior Software Engineer to join our FinOps team in London. ASOS runs a large Azure estate behind a platform used by millions of customers, and every architectural decision made across our engineering teams has a cost attached to it. FinOps exists to make that cost visible, attributable and actionable - so teams can move fast without spend quietly compounding in the background. This is engineering, not reporting: the pipelines, tooling and guardrails you build are what give hundreds of ASOS engineers a clear view of what their services cost and what to do about it.

At this level your ownership sits at the system and cross-team level. You will take ambiguous, high-impact problems, set the technical direction within them, and deliver to production with confidence. You will be a strong voice in architectural and cross-team decisions, working closely with the Engineering Lead, other Senior Engineers, and Finance to shape how ASOS understands and controls cloud cost.

In this role, you will own significant parts of our FinOps platform end to end. You'll build the cost and usage data pipelines that everything else depends on, the allocation and showback models that tell teams what is theirs, and the guardrails that keep the estate tidy by default. Alongside that, you'll work directly with Product Delivery Teams on the optimisation work itself - right-sizing, commitment strategy, architectural change - and quantify the impact so the result is provable rather than claimed.

This is a role for an engineer who finds cost a genuinely interesting engineering problem rather than an accounting one. The best cost saving is almost always the one an engineering team chooses to make, which means the job is as much about evidence, clarity and influence as it is about code. If you like building things that change how other engineers make decisions, this is the right role.

The primary customers of this team are the Product Delivery Teams across ASOS, and the measure of success is not whether we shipped a dashboard - it is whether those teams trust the numbers, act on them, and are making better architectural calls because of what we built.

Our north star is simple: any engineer at ASOS should be able to see what their services cost, understand why, and know what to do about it - without asking Finance or FinOps to find out for them. That is what we are building.

Within six months, a strong senior engineer in this team will own a meaningful part of the FinOps platform, have delivered measurable and defensible savings alongside engineering teams, and be the person other engineers come to before they make an expensive architectural decision.

What You'll Be Doing

• Design and deliver the data products that make Azure cost visible and attributable across ASOS - cost and usage pipelines, allocation and showback models, anomaly detection, and the reporting surfaces engineering and Finance actually use.

• Own the cost and usage data platform on Databricks: ingesting Azure Cost Management exports, reservation and Savings Plan data, resource inventory and tagging metadata into Delta Lake, and modelling it into datasets that engineering and Finance both trust.

• Build and own the Power BI semantic models behind cost reporting - DAX measures, composite and DirectQuery designs, and model definitions managed as code through TMDL and XMLA rather than clicked together by hand.

• Lead optimisation work across the estate - right-sizing, autoscaling behaviour, storage tiering, data transfer and egress patterns, orphaned resource cleanup - and quantify the impact so every saving is evidenced rather than asserted.

• Own our reserved capacity and Savings Plan strategy in partnership with Finance, modelling commitment scenarios against real usage patterns and the seasonal demand curves that come with retail.

• Build the guardrails that keep the estate allocatable by default - tagging and allocation policy, Azure Policy, budget controls, and exception reporting that makes unattributable spend visible - so cost hygiene does not depend on people remembering.

• Develop the unit economics that connect spend to value - cost per order, per customer, per request - so efficiency can be judged against what the business gets, not just against last month's bill.

• Engage directly with Product Delivery Teams as the primary customers of FinOps: reviewing architectures, quantifying trade-offs, and making the efficient path the easy one. This is where you will build the relationships and platform knowledge that give you real influence over what gets built next.

• Set the technical direction for FinOps engineering at ASOS - data architecture, modelling patterns and standards - and bring others with you through design review, code review and mentoring.

• Support forecasting, budgeting and variance analysis with Finance, and help explain movements in spend in terms that both engineers and Finance recognise.

• Help shape how FinOps uses agentic AI - not just adopting tools, but rethinking how cost investigation, pipeline development and reporting work when agents are part of the equation. You'll experiment with both GitHub Copilot and Claude workflows, document what you learn, and influence the team's direction.

• Write high-quality, well-tested code using a test-first approach, and work with Cyber Security to keep access standards and compliance requirements embedded by default rather than bolted on.

What We're Using

• Python - cost and usage data pipelines, modelling, automation and analysis

• Power BI - our primary surface for cost visibility: DAX, TMDL, composite and DirectQuery models, and XMLA endpoints for managing semantic models programmatically

• Databricks - Delta Lake and SQL warehouses, where our cost and usage data is processed, modelled and served

• KQL (Kusto Query Language) - querying Azure Monitor, Log Analytics and resource telemetry

• Azure - Cost Management and Billing, Advisor, Azure Policy and Monitor, plus the full breadth of services our estate actually runs on

• GitHub and GitHub Actions - source control, automation, and CI/CD

• Azure DevOps - work item tracking and pipeline management

• GitHub Copilot and Claude Code - we use both, choosing each based on the problem. Copilot for IDE-integrated agent work, Claude Code for terminal-based multi-file refactors. System context and reliability matter as much as speed.

• Beyond technical chops, we're looking for engineers with an agentic mindset. This means you see GitHub Copilot and Claude not as shortcuts, but as design partners that change how we approach problems - from investigating a cost anomaly to building the pipeline that would have caught it. If you get excited about pushing tools to new places and bringing colleagues along, this is the role.

Qualifications

Additional Information

What's in it for you?

• Competitive salary, pension, and private medical care scheme
• Performance related bonus
• Flex benefits allowance - which you can chose to take as extra cash, or use towards other benefits
• 25 days paid annual leave + an extra day for your birthday
• Employee discount (hello ASOS discount!)
• Tech Develops - our internal tech focussed skills development programme to focus on your personal growth as a technologist
• Opportunity to represent ASOS at industry leading events
• Opportunity to help shape and drive our DE&I initiatives in Tech (like our WIT movement and Diversity mentoring in Tech)
• Opportunity to make an impact from day one and work with the latest in cutting edge of technology