Senior Software Engineer

We're ASOS, the online retailer for fashion lovers all around the world.

We exist to give our customers 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 judgement, and channel your creativity into a platform used by millions.

We're proud members of Inclusive Companies; are Disability Confident Committed and have signed the Business in the Community Race at Work Charter. Everyone needs some help showing up as their best self, so let our Talent team know if you need any adjustments throughout the process in whatever way works best for you.

We believe being together in person helps us move faster, align more effectively, and build stronger teams. Our approach includes spending at least two days a week in the office to support collaboration, decision-making, and shared ownership.

We’re looking for a Senior Software Engineer to join our Developer Experience team in London. Developer Experience is the team responsible for the internal developer platform at ASOS: Backstage, our developer portal, golden path templates, engineering metrics, and the agentic AI capabilities that are fundamentally changing how engineers work. The goal is always the same: reduce the cognitive load on engineers so they can focus on building things that matter for the business.

At senior level your ownership sits at the system and architectural level. As an individual contributor you will be the person others look to for technical decisions, design direction, and engineering quality on the platform. You are not just delivering features; you are shaping how the platform is built and setting the standards the whole team works to.

In this role, you will take technical ownership of significant parts of the Developer Experience platform. You’ll lead the design and delivery of complex features, set engineering standards within the team, mentor more junior engineers, and play a direct role in shaping how the platform evolves. The end-user of everything you build is a fellow engineer at ASOS, and every improvement you make is multiplied across hundreds of people, returning time that would otherwise be lost to toil, setup, or unnecessary complexity. The measure of a great developer platform is whether a new engineer can onboard into their team and get their first service into production without needing to ask anyone for help. That is what we are building.

This is a role for a senior engineer who combines deep technical capability with genuine product thinking, who operates comfortably across the full breadth of a platform stack, and who is energised by solving hard problems that make other engineers more productive. We want someone who ships, learns, and iterates, not someone who plans endlessly.

Platform Ownership & Delivery

• Lead the design and delivery of complex features across Developer Experience services, covering Backstage, golden path templates, engineering metrics, DORA instrumentation, and AI-assisted developer tooling.
• Take architectural ownership of key Developer Experience components, making clear, well-reasoned technical decisions and ensuring they scale across a diverse engineering organisation.
• Design and evolve Backstage plugins, scaffolder templates, and catalogue integrations that make the developer portal the single trusted starting point for engineers at ASOS.
• Own the engineering quality of golden path templates, ensuring they reflect current best practices, cover the right service archetypes, support ASOS canonical languages and frameworks, and include security, observability, and CI/CD by default.
• Drive the team’s work on DORA and developer productivity instrumentation, designing measurement approaches that give real visibility into deployment frequency, lead time, collaboration score, and developer satisfaction, surfacing these signals to engineering management so they can identify and remove friction across their teams.

Agentic AI & Developer Tooling

• Play a leading technical role in embedding agentic AI capabilities into the ASOS developer experience, working closely with OCTO (Office of the CTO) to shape and integrate AI-powered workflows into the portal and toolchain. You do not need to have done this before at scale; you need to be the kind of engineer who runs toward it, moves fast, and figures it out.
• Design and implement AI agent platform integrations using GitHub Copilot, MCP servers, and related tooling, making AI assistance a natural part of how engineers at ASOS work.
• Work in lockstep with the Engineering Lead and in close collaboration with OCTO to assess the agentic AI tooling landscape as it evolves, evaluating tools across workflow benefit, model cost, and capability for multi-step agentic tasks, and translating that analysis into clear guidance on what we use, when, and why.
• Take a leading role in shaping how Developer Experience evolves for an agentic engineering model, not just adopting tools, but redesigning how golden paths, system templates, and onboarding work when AI agents are part of the engineering workflow. You will define the approach, run experiments across GitHub Copilot and Claude workflows, and establish the patterns the rest of the team builds from.
• Contribute to evaluation frameworks and guardrails for AI-assisted engineering, ensuring the team can measure quality, manage regression, and adopt AI safely at scale.

Engineering Leadership

• Set technical direction within the DevEx team, contributing to architectural decisions, defining standards, and ensuring the platform is built to last.
• Mentor and develop junior and mid-level engineers through code review, pairing, design conversations, and direct feedback that accelerates their growth.
• Champion automated testing, documentation-as-code, and engineering excellence across everything the team ships.
• Work with the Engineering Lead to shape the team’s roadmap, sequence delivery, and communicate technical trade-offs clearly to stakeholders.

Cross-Domain Collaboration

Your technical credibility is what earns you a seat at the table with adjacent teams (not organisational seniority). The collaboration below is a consequence of the engineering you do, not a separate workstream.

• Partner with Release Engineering, Developer Infrastructure, and Cyber Security to ensure the Developer Experience platform integrates cleanly with the wider ecosystem, with security, compliance, and access standards embedded by default, not bolted on.
• Engage directly with product engineering teams, understanding the friction they face, gathering feedback on portal and template adoption, and using those insights to improve the platform.

What we are using 

• Backstage - our internal developer portal (catalogue, scaffolder, TechDocs, plugins)
• TypeScript, React and Node.js - portal frontend, plugin development, and backend services
• GitHub and GitHub Actions - source control, automation, and CI/CD
• Azure - cloud hosting, identity, and storage for Developer Experience services
• Docker and containers - building and running platform services
• AI tooling - AI coding assistants embedded into our engineering workflows, in partnership with OCTO. At senior level, your job is to know which tool to reach for and to set the pattern for the team.
• Engineering metrics, DORA instrumentation, and DX/SPACE signals
• Azure DevOps - work item tracking and pipeline management

Beyond technical depth, we are looking for engineers with a genuine agentic mindset. At senior level this means more than using the tools - it means seeing how agentic workflows reshape the entire developer platform, from golden paths to onboarding to how teams reason about service ownership. You will be one of the people who defines what that looks like at ASOS.

At senior level we are looking for engineers who bring deep technical expertise, strong independent judgement, and a track record of owning and delivering complex platform work. This is an individual contributor role; you will be the technical authority on what you own, with the space and trust to make real decisions.

Required Skills and Experience

• Proven experience delivering production-grade software in a platform, developer experience, or internal developer platform team; you know what it means to build for engineers as customers.
• Deep proficiency in TypeScript/JavaScript and/or a primary backend language (C#/.NET, Node.js, or Go); you write idiomatic, performant, production-ready code.
• Proven experience with Git, including branching strategies and pull request workflows, with a consistent track record of clean, well-structured code reviews and setting the quality bar for the team.
• Experience with Backstage or a comparable internal developer portal, with the credibility and drive to become the technical authority on it quickly. Depth in catalogue modelling, plugin development, scaffolder templates, or TechDocs is a strong advantage.
• Solid understanding of CI/CD, modern software delivery practices, and golden path approaches, and the ability to make developer onboarding fast, consistent, and safe.
• Confident with containers (Docker), GitHub Actions or Azure Pipelines, and Azure platform fundamentals.
• Experience with React and component-based frontend development; you can build and maintain developer portal UIs to a high standard.
• Hands-on experience using agentic AI tools (GitHub Copilot, Claude Code, or equivalent) as a core part of your engineering workflow. At senior level, we expect you to go further than using these tools - you should be able to evaluate them critically, design the system context and patterns that make agents reliable at scale, and lead the team’s thinking on where agentic approaches add the most value.
• A track record of setting technical direction, making architecture decisions, and delivering shared platforms used by multiple product teams.
• Strong collaborator, comfortable working across platform engineering, application engineering, security, and product teams, and able to explain technical decisions without hiding behind jargon.
• Experience mentoring engineers, running effective code reviews, and contributing to a culture of engineering excellence.

We'd Love It If You Have

• Experience with MCP server integration, LLM tool use patterns and building AI-assisted developer workflows beyond standard Copilot usage.
• Experience with DORA metrics, developer productivity instrumentation, or DevEx research methods (surveys, journey mapping, friction logs).
• Familiarity with platform/product thinking frameworks: paved roads, fitness functions, service ownership taxonomy.
• Experience with CLI tooling design, documentation pipelines, or service catalogue governance models.
• Knowledge of evaluation and guardrail design for AI features in an engineering context.

BeneFITS'

• Employee discount (hello ASOS discount!)
• Employee sample sales
• 25 days paid annual leave + an extra celebration day for a special moment
• Private medical care scheme
• Flexible benefits allowance - take it as extra cash or use it towards other benefits
• Opportunity to represent ASOS at industry-leading events

Why take our word for it? Search #InsideASOS on our socials to see what life at ASOS is like.