Senior iOS Mobile Engineer (124)

JSG (Johnson Service Group, Inc.); Toronto; Hybrid; CAD 120,000 - 160,000; Full time

Job summary

Johnson Service Group, Inc. is seeking a Senior iOS Mobile Engineer to design, develop, and maintain scalable iOS applications in a hybrid Toronto environment (2 days in office per week).

You will work with product, design, QA, and other developers to deliver high-quality mobile experiences. The role requires strong Swift expertise, proficiency with SwiftUI, Xcode, REST/GraphQL, CoreData, and modern architectures (MVC, MVVM, Clean).

Qualifications

• 9–10 years of hands-on iOS development experience.
• Strong Swift skills and knowledge of modern iOS frameworks.
• Experience with SwiftUI, Xcode, REST/GraphQL integration, and data persistence.
• Proficiency in testing (XCTest) and TDD practices.
• Familiarity with modern architectures (MVC, MVVM, Clean).
• Ability to work with Git and collaborate across teams.
• Strong debugging, profiling, and performance optimization capabilities.

Responsibilities

• Design, develop, and maintain high-quality iOS applications and features.
• Collaborate with product managers, designers, QA, and other developers to craft great mobile experiences.
• Translate business requirements into scalable technical solutions.
• Work with cross-functional teams, manage dependencies, and resolve challenges independently.
• Participate in code reviews and contribute to engineering best practices.
• Identify, troubleshoot, and resolve performance, stability, and usability issues.
• Continuously improve application quality, performance, and maintainability.

Skills

Swift proficiency

SwiftUI

iOS frameworks

Xcode expertise

REST APIs integration

GraphQL experience

CoreData

Keychain / UserDefaults

TDD / XCTest

Performance profiling

MVC / MVVM / Clean Architecture

Problem solving / debugging

Independent ownership

Tools

Xcode

Job description

Our client is seeking a Senior iOS Mobile Engineer to design, develop, and maintain scalable, high-performing iOS applications while collaborating with cross-functional teams to deliver exceptional mobile experiences. (Toronto, Hybrid, 2 days in office/wk)

Must Have Skills

• 9-10 years of hands-on iOS application development experience.
• Strong proficiency in Swift, including protocols, generics, and functional programming concepts.
• Experience building applications using SwiftUI and modern iOS frameworks.
• Expertise with Xcode for development, debugging, performance optimization, and profiling.
• Experience integrating REST APIs, GraphQL, JSON, and third-party services.
• Knowledge of CoreData, Keychain, and UserDefaults for data persistence.
• Experience with XCTest, XCUI, and Test-Driven Development (TDD).
• Strong Git-based source control and collaborative development practices.
• Experience using Xcode Instruments and Memory Graph to analyze and optimize application performance.
• Strong understanding of MVC, MVVM, and Clean Architecture design patterns.
• Excellent problem-solving, debugging, and troubleshooting skills.
• Proven ability to work independently with strong ownership and accountability.

Nice to Have Skills

• Backend development experience.
• Passion for learning and adopting emerging iOS technologies.

Responsibilities

• Design, develop, and maintain high-quality iOS applications and new features.
• Collaborate with product managers, designers, QA engineers, and fellow developers to deliver exceptional user experiences.
• Translate business requirements into scalable, maintainable technical solutions.
• Work effectively with cross-functional teams while managing dependencies and resolving technical challenges independently.
• Participate in code reviews and contribute to engineering best practices.
• Identify, troubleshoot, and resolve application performance, stability, and usability issues.
• Continuously improve application quality, performance, and maintainability.