IOS Engineer

TEKsystems; City of Westminster; Hybrid; GBP 101,000 - 166,000; Full time

Job summary

TEKsystems in London is seeking an iOS Engineer to join a global payments organisation and contribute to native mobile applications used by tens of millions of customers. This is a hands-on role for someone with strong Swift fundamentals, a quality-focused approach and a passion for scalable customer experiences.

You will collaborate with Product, Design, QA and backend teams to design, build and improve features across the full delivery lifecycle.

Qualifications

• Bachelor’s degree in CS or equivalent required.
• Strong Swift fundamentals with SwiftUI experience.
• Experience with REST APIs and mobile CI/CD tooling.

Responsibilities

• Design, build and maintain native iOS features using Swift.
• Develop polished customer-facing experiences using SwiftUI and UIKit.
• Take ownership from requirements to production.
• Integrate iOS apps with REST APIs and backend services.
• Contribute to architecture discussions and testing.
• Write clean, modular, testable code.
• Build unit/UI automation with XCTest and XCUITest.
• Refactor and modernise Objective-C codebases.
• Investigate production defects and performance issues.
• Collaborate with Product, Design, QA and backend teams.

Skills

Swift

SwiftUI

UIKit

REST APIs

XCTest

XCUITest

MVVM

Type-safe modelling

Unit testing

Education

Bachelor’s degree in CS

Tools

Tuist

xcodebuild

GitHub Actions

CircleCI

RAML

Job description

• Micro-feature architecture

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