macOS Endpoint Security Engineer

This position is listed on behalf of a partner company, who manages all applications and next steps. Our partner is looking for a macOS Endpoint Security Engineer based in the United States.
We are looking for an experienced macOS Endpoint Security Engineer to contribute to the development of advanced endpoint protection technology. In this role, you will work on a sophisticated security sensor designed to monitor file, process, network, and identity activity, prevent malicious behavior, and deliver security telemetry to cloud-based systems. You will focus on low-level macOS systems programming, building reliable and high-performance software using modern C++ and Swift. Working within a cross-platform engineering environment, you will help maintain shared codebases supporting macOS, Windows, and Linux. The position requires strong expertise in concurrency, memory management, debugging, and performance optimization. This is an opportunity to tackle complex cybersecurity challenges while strengthening the security and reliability of enterprise devices.

Accountabilities:

Develop, enhance, and maintain macOS endpoint security components using modern C++ (C++17/C++20), Swift 6, and Objective-C++.

Contribute to the development of an endpoint security sensor that monitors file, process, network, and identity activities, blocks malicious behavior, and transmits security telemetry.

Implement and maintain macOS System Extensions and Endpoint Security clients, including authorization (AUTH) events, notification events, user and MDM approval workflows, and extension upgrades.

Develop and optimize system-level components using Foundation, CoreFoundation, Grand Central Dispatch (GCD), pthreads, POSIX/BSD APIs, Mach IPC, launchd, and XPC.

Build and maintain network security capabilities using Network Extensions, including flow-level and packet-level content filtering, and Network.framework.

Implement security mechanisms involving code-signature verification, certificate validation, Keychain, entitlements, hardened runtime, and macOS privacy permissions.

Support hardware and storage-related functionality through IOKit and DiskArbitration.

Optimize application performance, concurrency, CPU utilization, and memory consumption to ensure high reliability and minimal system overhead.

Investigate and resolve complex technical issues using Instruments, os_signpost, LLDB, crash logs, and os_log.

Develop and maintain automated tests using XCTest, sanitizers, fuzz testing, and xcodebuild-based continuous integration pipelines.

Ensure software compatibility across Apple Silicon and Intel-based Mac systems.

Collaborate with cross-platform engineering teams to maintain shared codebases supporting macOS, Windows, and Linux.

Contribute to application packaging, installation, notarization, and deployment through MDM solutions such as Jamf and Microsoft Intune.

Support software quality, secure development practices, and production reliability throughout the development lifecycle.

Requirements:

6–10 years of professional software engineering experience, with consideration for more senior candidates.

Strong proficiency in modern C++, particularly C++17/C++20, and Swift 6, including async/await, actors, and strict concurrency checking.

Hands-on experience with Objective-C++ and integrating Swift, C++, and C APIs.

Strong macOS systems programming knowledge, including Foundation, CoreFoundation, GCD, pthreads, POSIX/BSD APIs, and Mach IPC.

Experience with launchd daemons and agents, XPC C APIs, and NSXPCConnection.

Practical experience in at least one or more of the following areas:

Endpoint Security and System Extensions: Endpoint Security clients, authorization and notification events, extension approvals, MDM integration, and