Darwin Runtime Engineer, Core OS

Relha LLC; Cupertino, Northern (CA, KY); Hybrid; USD 180,000 - 240,000; Full time

Job summary

Apple's Darwin Runtime team seeks visionary engineers to push the boundaries of low-level system technologies. If you obsess over performance, security, and the cascading impact of your code, your life's best work awaits.

You will drive design discussions, mentor peers through code reviews, and own critical components—from GCD to IPC and malloc—ensuring the OS and hardware breathe as one across iOS, macOS, watchOS, tvOS, and Vision Pro.

Qualifications

• Fluency in the C programming language.
• Experience with UNIX-like systems.
• System design and architecture skills.
• Strong understanding of operating system fundamentals such as threading, synchronization primitives, IPC, scheduling, and virtual memory.
• Excellent collaborative skills, with the ability to work with a team to design system architecture.

Responsibilities

• Drive critical design discussions and elevate peers through code reviews.
• Push the boundaries across a spectrum of low-level system technologies.
• Operate autonomously and take ownership of key components from design to delivery.

Skills

C programming

UNIX-like systems

System design

OS fundamentals

Collaboration

Education

BS/MS in Computer Science

Job description

For the engineer who obsesses over the butterfly effect of a single line of code, there is no greater stage than Apple's Core OS! Core OS builds uncompromising, lightning-fast foundation that iOS, macOS, watchOS, tvOS, and visionOS stand upon. We don't just write software; we forge the soul of the machine, ensuring the operating system and the hardware breathe as one to create a seamless device identity.

At the center of it all is Darwin, the UNIX-like heartbeat of Apple's operating systems, spanning from the deepest levels of the kernel up through critical low-level user components. The Darwin Runtime team is seeking visionary engineers to push the boundaries of low-level system technologies. If you obsess over performance, security, and the massive cascading impact of your code, your life's best work is waiting for you here!

Description

The Darwin Runtime team is responsible for the development and evolution of low-level user space libraries such as Grand Central Dispatch (GCD), Inter-Process Communication (IPC) technologies like XPC, pthread, and malloc, among others. The foundational libraries built by our team are the invisible engines powering the iPhone, iPad, Mac, Apple Watch, Apple TV, and the groundbreaking Vision Pro. We want an engineer with the drive to operate autonomously, the hunger to master new domains, and the ambition to step into technical leadership. Here, your voice shapes the future. You will drive critical design discussions, elevate peers through code reviews, and push the boundaries across a spectrum of technologies. Our environment fosters a culture of deep technical innovation, massive autonomy, and true ownership.

Minimum Qualifications

• Fluency in the C programming language
• Experience with UNIX-like systems
• System design and architecture skills
• Strong understanding of operating system fundamentals like threading, synchronization primitives, inter-process communication, scheduling, and virtual memory
• Excellent collaborative skills, with the ability to work with a team to design system architecture
• BS or MS in Computer Science or equivalent degree

Preferred Qualifications

• Knowledge of operating system implementation, hardware architecture and assembly programming
• Knowledge of Swift or Objective-C
• Skilled at interface and/or API design
• Experience with lldb or gdb
• Experience using Gen AI tools for Software Development