Sr. iOS Developer; onsite, NYC or Chicago

Sr. iOS Developer (Onsite, NYC)

Publicis Sapient is a digital transformation partner helping established organizations get to their future, digitally enabled state, both in the way they work and the way they serve their customers. We help unlock value through a start-up mindset and modern methods, fusing strategy, consulting, and customer experience with agile engineering and problem-solving creativity. United by our core values and our purpose of helping people thrive in the brave pursuit of next, our 20,000+ people in 53 offices around the world combine experience across technology, data sciences, consulting, and customer obsession to accelerate our clients' businesses through designing the products and services their customers truly value.

• At Publicis Sapient, we help organizations unlock value through digital business transformation—building products and platforms that matter to our clients and their customers.
• As a Senior iOS Developer, you will lead the design and development of scalable, high-performance mobile applications using modern iOS frameworks and architectural principles.
• You will collaborate across product, design, and engineering teams to deliver seamless, accessible, and data-driven user experiences while shaping engineering practices and mentoring team members.
• This role combines deep technical expertise with ownership, enabling you to influence mobile strategy, architecture, and delivery in a fast-paced, client-focused environment.

• Design, build, and maintain a robust, scalable multi-module iOS codebase using Swift and SwiftUI with clear modular boundaries and separation of concerns
• Collaborate with Product, UX, Design, and backend teams to translate requirements into polished user experiences and scalable design systems
• Build and evolve a reusable component library in SwiftUI with a scalable design token system and custom theming capabilities
• Apply architectural patterns (MVVM, Clean Architecture, etc.) to ensure a principled, testable, and maintainable codebase
• Develop local orchestration engines using BGTaskScheduler, Swift Concurrency (async/await, actors), and Combine for managing background and long-running tasks
• Design and maintain battery-efficient background location tracking solutions using Core Location (CLLocationManager, geofencing, significant-change monitoring)
• Implement feature flagging mechanisms (Firebase Remote Config, Launch Darkly, etc.) to support experimentation, controlled rollouts, and rollback strategies
• Integrate and maintain analytics pipelines (Firebase Analytics, Mixpanel, etc.) and enforce event taxonomy and schema governance in collaboration with Product and Data teams
• Ensure accessibility standards (WCAG 2.1 AA, Voice Over, Dynamic Type, touch target sizing) are embedded across the UI and design system
• Shape CI/CD pipelines (Xcode Cloud, Git Hub Actions, Fastlane) with automated quality gates and performance regression checks
• Implement APM and performance monitoring tooling (Firebase Performance, New Relic, Metric Kit) for application health and optimization
• Leverage AI-assisted development tools (e.g., Git Hub Copilot, Claude) and agentic workflows to accelerate development and reduce repetitive tasks
• Mentor and support junior and mid-level engineers, contributing to team growth, engineering quality, and knowledge sharing

• Strong experience building iOS applications using Swift
• Hands-on expertise with SwiftUI and modern UI architecture
• Experience designing scalable mobile architectures (e.g., MVVM, Clean Architecture)
• Proven experience building modular codebases and reusable UI component systems
• Experience working with concurrency models (async/await, Combine, background processing)
• Solid understanding of mobile performance optimization, including memory, CPU, and battery usage
• Experience integrating analytics frameworks and implementing event tracking systems
• Familiarity with feature flagging, experimentation frameworks, and release management practices
• Experience with CI/CD pipelines and mobile build/release tooling
• Strong debugging, problem-solving, and system design skills
• Experience…