iOS Engineer

iOS Engineer Location: London, hybrid working with three days per week onsite Contract: Initial 12-month contract Working Environment: Customer-facing mobile engineering Sponsorship: This position cannot offer visa sponsorship The Opportunity We are looking for an iOS Engineer to join a global payments organisation and contribute to native mobile applications used by tens of millions of customers worldwide. This is a hands-on engineering role for someone with strong Swift fundamentals, a quality-focused approach and a genuine interest in building reliable, intuitive customer experiences at scale. Working within a collaborative mobile engineering team, you will partner closely with Product, Design, QA, backend and fellow mobile engineers to design, build and improve customer-facing features. You will take ownership across the full delivery lifecycle, from understanding requirements and shaping technical solutions through to implementation, automated testing, release and production support. The environment moves quickly while maintaining a high engineering bar. You should be comfortable navigating ambiguity, communicating technical decisions clearly and delivering maintainable solutions within a mobile codebase. What You'll Do

• Design, build and maintain native iOS features using Swift
• Develop polished customer-facing experiences using SwiftUI and UIKit
• Take ownership of features from requirements and technical design through to production
• Integrate iOS applications with REST APIs and backend services
• Contribute to architecture discussions and technical decision-making
• Apply type-safe modelling to application data, state and business logic
• Write clean, modular, maintainable and testable code
• Build unit and UI automation using XCTest and XCUITest
• Refactor existing code and support the modernisation of legacy Objective-C components
• Investigate and resolve production defects, crashes and performance issues
• Analyse and optimise application performance, stability and responsiveness
• Contribute to code reviews and wider mobile engineering standards
• Support continuous integration, automated testing and mobile release processes
• Collaborate closely with Product Managers, Designers, QA Engineers and backend teams What You'll Bring
• developing native iOS applications
• Deep, recent hands-on exposure with Swift
• Strong exposure across SwiftUI and UIKit
• A solid understanding of Swift's type system and type-safe modelling
• Exposure with architectural patterns such as MVVM
• Exposure to consuming and integrating REST APIs
• Strong automated testing exposure using XCTest and/or XCUITest
• Exposure to designing modular, testable and maintainable application code
• Confidence debugging complex issues and analysing application performance
• Exposure to supporting production applications used by large customer bases
• Strong communication skills and the ability to explain technical decisions, trade-offs and implementation approaches clearly
• Ability to write and reason through Swift code independently
• Exposure to working within cross-functional, agile product teams
• A bachelor's degree in Computer Science or equivalent Desirable
• Worked with or modernising Objective-C codebases
• Micro-feature architecture or µFeatures
• Tuist and xcodebuild
• GitHub Actions, CircleCI or comparable mobile CI/CD tooling
• RAML or similar API documentation formats
• Open-source contributions
• Worked within payments, financial services, commerce or another regulated environment
• Worked delivering mobile products at significant customer scale Technology Environment
• Swift
• SwiftUI
• UIKit
• Objective-C
• MVVM
• REST APIs
• XCTest
• XCUITest
• Tuist
• xcodebuild
• GitHub Actions
• CircleCI
• Micro-feature architecture
• RAML Why Join? This is an opportunity to contribute to mobile products used by tens of millions of customers globally while working within a recognised Fortune 100 organisation. You will join a collaborative engineering environment where architecture, automated testing, production ownership and long-term application quality are treated as core parts of software delivery. The position offers the pace and visibility of a focused product team, combined with the scale, stability and technical complexity of a major global payments business. Interview Expectations The interview process will assess more than familiarity with iOS technologies. Candidates should be prepared to:
• Discuss previous projects and individual contributions in depth
• Clarify requirements before proposing a solution
• Explain architectural and implementation decisions independently
• Demonstrate strong Swift fundamentals and type-safe modelling
• Work through coding problems clearly and simply
• Explain testing strategies and production ownership
• Write code independently without relying on AI-assisted development tools Important Information This position requires attendance in the London office three days per week. Applicants must already hold the unrestricted right to work in the UK, as visa sponsorship is not available for this opportunity. Job Title: IOS Engineer Location: Victoria, UK Job Type: Contract Trading as TEKsystems. Allegis Group Limited, Maxis 2, Western Road, Bracknell, RG12 1RT, United Kingdom. No. 2876353. Allegis Group Limited operates as an Employment Business and Employment Agency as set out in the Conduct of Employment Agencies and Employment Businesses Regulations 2003. TEKsystems is a company within the Allegis Group network of companies (collectively referred to as "Allegis Group"). Aerotek, Aston Carter, EASi, Talentis Solutions, TEKsystems, Stamford Consultants and The Stamford Group are Allegis Group brands. If you apply, your personal data will be processed as described in the Allegis Group Online Privacy Notice available at https://www.allegisgroup.com/en-gb/privacy-notices. To access our Online Privacy Notice, which explains what information we may collect, use, share, and store about you, and describes your rights and choices about this, please go to https://www.allegisgroup.com/en-gb/privacy-notices. We are part of a global network of companies and as a result, the personal data you provide will be shared within Allegis Group and transferred and processed outside the UK, Switzerland and European Economic Area subject to the protections described in the Allegis Group Online Privacy Notice. We store personal data in the UK, EEA, Switzerland and the USA. If you would like to exercise your privacy rights, please visit the "Contacting Us" section of our Online Privacy Notice at https://www.allegisgroup.com/en-gb/privacy-notices for details on how to contact us. To protect your privacy and security, we may take steps to verify your identity, such as a password and user ID if there is an account associated with your request, or identifying information such as your address or date of birth, before proceeding with your request. If you are resident in the UK, EEA or Switzerland, we will process any access request you make in accordance with our commitments under the UK Data Protection Act, EU-U.S. Privacy Shield or the Swiss-U.S. Privacy Shield.