Required · Languages: modern C++ (C++17/20) and Swift 6 (async/await, actors, strict concurrency checking). Also Objective-C++ to bridge Swift, C++ and C APIs. · macOS systems programming: Foundation and CoreFoundation, GCD and pthreads, POSIX/BSD APIs, Mach IPC, launchd daemons and agents, and XPC (C API and NSXPCConnection). · Performance, debugging and test: o Profiling CPU and memory with Instruments and os_signpost. o Debugging with LLDB, crash logs and os_log. o XCTest, sanitizers, fuzzing, and xcodebuild-based CI. o Apple Silicon and Intel. · Experience with codebases shared across Mac, Windows and Linux. Core skills (one or more of the areas listed below) · Process model and IPC: launchd daemons and agents, and XPC (C API and NSXPCConnection). · Endpoint Security and System Extensions: Endpoint Security clients handling both blocking (AUTH) events and notification events, user/MDM approval, upgrades. · Network Extension: content filters, both flow-level (NEFilterDataProvider) and packet-level (NEFilterPacketProvider), and Network.framework. · Security and crypto: Verifying code signatures (SecCode / SecStaticCode) and validating certificates (SecTrust), Keychain, Entitlements, hardened runtime, and macOS privacy permissions. · Devices and storage: IOKit (hardware and device enumeration) and DiskArbitration (disk and volume events). · Packaging and deployment: installers, notarization, and MDM configuration profiles deployed through Jamf, Intune or similar tools. · Performance, debugging and test: Profiling CPU and memory with Instruments and os_signpost, Debugging with LLDB, crash logs and os_log, XCTest, sanitizers, fuzzing, and xcodebuild-based CI. Nice to have · UI: SwiftUI and AppKit apps and app extensions. · Testing against macOS and Xcode betas before public release. · Experience shipping EDR/AV, network security or device-management products.