iOS Engineer

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 We're looking for a Mid-level iOS Engineer to join our Analytics & Experimentation Product Delivery Team and own how customer behavior is captured in our iPhone and iPad apps. This role is about building reliable, well‑governed analytics and experimentation instrumentation at scale, and working collaboratively with product and engineering teams across ASOS to make the data they depend on trustworthy. Our app is used by over 8 million active users globally, maintains an excellent App Store rating, and is built using modern iOS technologies including the latest versions of Swift. You'll be contributing to a mature, well‑supported platform where quality, reliability and user experience matter — and you'll be the iOS voice in a team that spans web, Android, back-end and analytics engineering. What you'll be doing: Implementing and maintaining analytics event tracking in the iOS app following iOS best practices and platform guidelinesWorking closely with product managers, analysts and data engineers to translate event specs into instrumentation, and making sure iOS events conform to the agreed schemas, naming conventions and data contractsCollaborating within an agile, cross‑functional team, and supporting other ASOS iOS teams who contribute tracking through our inner source model — reviewing pull requests and helping them validate their eventsInvestigating and resolving data quality issues, such as discrepancies between platforms or missing and incorrectly populated properties, and taking ownership through to a permanent fixSupporting experimentation on iOS, including Optimizely SDK integration, experiment exposure and variant events, and the operational monitoring behind themSupporting code quality, maintainability and testing so that tracking changes ship safely and behavioral data stays reliable Qualifications About you Experience building iOS applications using Swift and the core iOS frameworksExperience integrating third‑party SDKs into a production iOS app analytics, experimentation or similar (e.g. Mixpanel, Optimizely) or a strong appetite to pick this upAn understanding of how mobile events are batched, queued and flushed, and the trade‑offs between data completeness, battery and network performanceKnowledge of common software design patterns and architecture concepts, and an interest in designing instrumentation that's consistent and easy for other teams to adoptAn interest in writing clear, maintainable code and improving existing codebasesAwareness of privacy and consent requirements and how they apply to customer tracking on mobileComfortable debugging data problems as well as code inspecting payloads, comparing against expected output, and working with analysts to confirm a fix (SQL or Databricks familiarity is a bonus, not a must)Familiarity with unit testing and a willingness to contribute to test coverageExperience with UI automation tools Additional Information What's in it for you? Competitive salary, pension, and private medical care schemePerformance related bonusFlex benefits allowance - which you can chose to take as extra cash, or use towards other benefits25 days paid annual leave + an extra day for your birthdayEmployee discount (hello ASOS discount!)Tech Develops - our internal tech focussed skills development programme to focus on your personal growth as a technologistOpportunity to represent ASOS at industry leading eventsOpportunity 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