macOS Application Engineer Engineering San Francisco + 5

Phi Browser; San Francisco (CA); Hybrid; USD 120,000 - 180,000; Full time

Job summary

Phinomenon, with a global presence including San Francisco, London, Beijing, Shanghai and Shenzhen, is seeking a macOS Application Engineer to build the Phi Browser desktop experience using Swift, AppKit and SwiftUI. You will bring model-powered features into the macOS ecosystem and collaborate with frontend, backend and AI teams to deliver fast, reliable, and delightful user experiences.

You will optimize performance, manage sandboxing and notarisation, and contribute to testing, CI/CD, and

Qualifications

• Hands-on macOS development with Swift, AppKit/SwiftUI and polished apps.
• Experience sandboxing, entitlements, and notarisation.
• Experience integrating networked APIs (REST, WebSocket).
• Strong collaboration in remote teams.
• Ability to ship and maintain production-grade macOS apps.

Responsibilities

• Design, develop, and maintain production-grade macOS applications.
• Implement AI-enhanced features and offline capabilities.
• Optimize memory, CPU usage, UI rendering, and offline behaviour.
• Debug across macOS versions, manage sandboxing, entitlements, and packaging.
• Collaborate with UX, QA, and documentation teams.
• Maintain test coverage: unit/UI tests and CI/CD pipelines.
• Stay updated with Apple frameworks and platform APIs.

Skills

Swift

AppKit

SwiftUI

AI integration

Debugging

Performance

Tools

REST

WebSocket

CI/CD

Job description

# macOS Application Engineer## CategoryEngineering## Available in* San Francisco* London* Beijing* Shanghai* Shenzhen* Remote## About PhinomenonPhinomenon is built by browser and cloud veterans: our founders are behind FydeOS (a Chromium-based OS trusted by millions) and QingCloud (one of China's earliest API-first IaaS platforms, founded in 2012). Fresh off a healthy, eight-figure Series A raise, we have the runway to dream big without panicking about next week's payroll. With folks working from San Francisco, London, Beijing, Shanghai and Shenzhen, we are proudly global and friendly to your time zone, with overlapping hours so we can all actually talk. We ship fast and ship hard, but burnout is so last decade: we bake in wellness stipends, mandatory recharge days and flexible schedules, because great code comes from healthy lives. No timecards, no surveillance software, no weekend team-building. We'd rather hand you the best tools money can buy (Claude Max, ChatGPT Business and Cursor Ultra come standard) and trust you with them. We don't fetishise years of experience, degrees or big-tech logos, and fresh graduates are more than welcome: show us what you have built and how you think. If you want to build the nextgen browser that actually, you know, gets you, while still enjoying your evenings and maintaining upright posture, welcome home.## About the RoleAs our macOS Application Engineer, you'll architect and build the Phi Browser desktop experience: native features like context-aware assistants, offline-ready tools, and seamless UI that feels personal. You'll collaborate with frontend, backend, and AI teams to bring model-powered features right into the macOS ecosystem, delivering fast, reliable, and delightful user experiences.## Responsibilities* Design, develop, and maintain production-grade macOS applications using Swift, AppKit, and SwiftUI* Implement AI-enhanced features: inline suggestions, contextual pop-ups, real-time summarization* Optimize performance: memory, CPU usage, UI rendering, offline behaviour* Debug across macOS versions and manage sandboxing, entitlements, and packaging* Collaborate with cross-functional teams on UX, design, QA, and documentation* Maintain test coverage: unit tests, UI tests, and CI/CD pipelines* Stay current with the latest Apple frameworks, standards, and platform APIs## Requirements* Deep hands-on macOS app development with Swift and AppKit/SwiftUI. We don't count years, we look at what you've shipped; a polished indie app or student project counts.* Solid understanding of the macOS application lifecycle, sandboxing, entitlements, and notarisation* Experience integrating networked APIs (REST, WebSocket)* Strong proficiency in debugging, profiling, and optimizing app performance* Familiarity with packaging and distributing Mac apps through notarisation* Excellent collaboration and communication skills on a remote team## Nice to Have* Objective-C or C++ experience, or bridging mixed-language codebases* Knowledge of Core Animation, Core Data, AVFoundation, or File System APIs* Experience with AI/ML or embedding inference engines on-device* Contributions to open-source macOS tools or libraries* Experience shipping AI-powered desktop apps or featuresAnd should the future prove entirely too exhausting, there is a switch to disable all AI features. No offense will be taken.