Requirements

• Experience developing complex, system-level frameworks, daemons, or background services for iOS and macOS (beyond standard UI-focused app development).
• Strong programming proficiency in Swift, alongside experience with Objective-C or C/C++ for lower-level system integration.
• Deep understanding of concurrency (Swift Concurrency, GCD), memory management, and asynchronous network programming.

Nice to Haves

• Experience designing or evolving wire protocols (e.g., Protocol Buffers), data-streaming pipelines, or connection management.
• Hands-on experience with Apple's Inter-Process Communication (XPC) to bridge sandboxed applications and system services.
• Familiarity with secure communication protocols, cryptography, or privacy-preserving architectures.
• Working knowledge of ML concepts and frameworks and proficiency in performance profiling with Instruments, and experience implementing robust client-side telemetry and logging using native Apple APIs.
• Familiarity with end-to-end systems that span device, network, and server tiers, and comfort reasoning about failure modes across that boundary.

What You'll Be Doing

• Designing and evolving the on-device client SDKs and the XPC services they sit behind, balancing API ergonomics for client teams with the strict process-isolation and attestation guarantees required by PCC.
• Implementing high-throughput, low-latency request paths: protobuf serialization of inference payloads, payload compression, multi-turn session state and lifecycle, retry/cancellation semantics, and streaming of incremental model output back to clients.
• Owning concurrency and resource management across async/await, AsyncStream, and GCD — including correct cancellation, back-pressure, and lifetime management of long-lived XPC connections.
• Building the telemetry, signposts, and privacy-audited logging that let on-call engineers diagnose request failures across device, cloud, and inference layers without exposing user data.
• Collaborating closely with the PCC server-side, Foundation Models, attestation, and platform-frameworks teams; writing design documents, leading reviews, and mentoring engineers on Apple platform fundamentals.
• Profiling on real hardware with Instruments and driving down memory, latency, and energy costs in the request path — these libraries run on every device, on every inference, so every microsecond matters.