Darwin Runtime Engineer

Cupertino, California, United States Software and Services

The people here at Apple don’t just build products, we build the kind of wonder that revolutionise entire industries. Imagine what you could do here! Do you have a passion for understanding how each line of code affects all the others? In the Core Operating Systems group ensuring the OS is inseparable from each device’s identity as a whole. That’s because this group is committed to building fully integrated operating systems that combine hardware, software, and apps into a single Apple experience.

Your dedication to cross-disciplinary collaboration will help develop groundbreaking technologies, such as iOS, macOS, watch

OS, and tvOS. By crafting these distinct, complete user experiences, you’ll continue to uphold and advance the excellence people expect from Apple devices! The Darwin Runtime team in Core OS is looking for enthusiastic engineers interested in developing low-level system technologies for Apple’s operating systems.

The Darwin Runtime team is responsible for building the low-level runtime technologies like Grand Central Dispatch (GCD), secure inter-process communication systems, memory allocator, threading library, and concurrency and synchronization primitives. The team operates at the intersection of operating systems, programming language design, systems security, and high-performance computing. As a Software Engineer on the team, you'll work closely with kernel engineers, security architects, and framework developers to deliver foundational technologies that enable Apple's next-generation computing platforms.

The ideal candidate should be self-motivated and effective in operating independently, with a desire to learn and develop technical leadership. Team members are welcome and encouraged to participate in design discussions, code reviews, and development across multiple technologies. Our environment fosters technical innovation, meaningful technology ownership, and a liberating amount of autonomy!

• You will be responsible for working on a range of technologies that form the foundation of Apple’s operating systems. The work would include responsibilities such as:
• Design and implement new features and APIs for Darwin Runtime technologies like GCD, XPC, pthread, and malloc
• Design and implement IDL compiler frontend and backend systems, including lexical analysis, parsing, semantic analysis, and code generation for both C and Swift targets
• Develop and maintain high-performance runtime libraries that handle secure communication, memory management, and component lifecycle across different execution environments
• Optimize code generation, runtime performance, and memory usage to meet strict performance requirements for low-level systems
• An engineer in the Secure Runtime team would regularly:
• Participate in all phases of software development cycle: from problem definition and design, through implementation, testing, and debugging
• Diagnose and resolve issues across different layers of the stack
• Work with cross functional teams to enable developer and product requirements

• 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

• Experience with compiler design, including lexical analysis, parsing, semantic analysis, and code generation
• Knowledge of capability-based security models, sandboxing, and secure IPC mechanisms
• 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

At Apple, base pay is one part of our total compensation package and is determined within a range. This provides the opportunity to progress as you grow and develop within a role. The base pay range for this role is between $126,800 and $220,900, and your base pay…