Senior iOS Engineer — SwiftUI, MVVM & Performance

JOHNSON SERVICE GROUP; Toronto; Hybrid; CAD 110,000 - 160,000; Full time

Job summary

Johnson Service Group in Toronto, Canada, seeks a Senior iOS Mobile Engineer to design, develop, and maintain scalable, high-performing iOS apps. Hybrid role requiring 2 days in the office per week, collaborating with cross-functional teams to deliver exceptional mobile experiences.

The ideal candidate has 9–10 years of iOS development, strong Swift skills, SwiftUI, Xcode, REST/GraphQL, CoreData, Keychain, and tests (XCTest/XCUI, TDD).

Qualifications

• 9–10 years of hands-on iOS development experience.
• Proficient in Swift with protocols, generics, and functional programming concepts.
• Experience with SwiftUI and modern iOS frameworks.
• Proficient 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 collaboration practices.
• Experience using Xcode Instruments and Memory Graph to analyze and optimize performance.
• Strong understanding of MVC, MVVM, and Clean Architecture design patterns.
• Excellent problem-solving and ability to work independently with ownership.

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 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

iOS development

Swift

SwiftUI

Xcode

REST APIs

GraphQL

JSON

CoreData

Keychain

UserDefaults

XCTest

XCUI

TDD

Git

Instruments

Memory Graph

MVC

MVVM

Clean Architecture

Problem Solving

Ownership

Tools

Memory Graph tooling

Instruments tooling

Job description

Johnson Service Group in Toronto, Canada, seeks a Senior iOS Mobile Engineer to design, develop, and maintain scalable, high-performing iOS apps. Hybrid role requiring 2 days in the office per week, collaborating with cross-functional teams to deliver exceptional mobile experiences.

The ideal candidate has 9–10 years of iOS development, strong Swift skills, SwiftUI, Xcode, REST/GraphQL, CoreData, Keychain, and tests (XCTest/XCUI, TDD).