Senior Networking Engineer

1. Role Mission

We're seeking a Senior Networking Engineer (Contract) to delivery expect-level development across our core networking product suite on Windows and macOS.

This role focuses on accelerating key technical milestones within our networking stack, ensuring system-level implementations are secure, performant, and tightly integrated with operating system frameworks.

This engagement is delivery focused. Success in this role is measured by the quality, stability, and production readiness of technical deliverables, as well as the smooth integration of new components into the existing platform.

The ideal candidate brings deep experience with OS-level networking APIs, system extensions, and high performance networking architecture, and can quickly contribute within an established engineering environment.

2. Engagement Model: "Project-Based Delivery"

This contract engagement centers on executing defined technical initiatives within our company's networking platform.

Areas of Focus

• System Extension Development
  Develop and maintain macOS System Extensions using the NetworkExtension framework in Swift and implement Windows Filtering Platform (WFP) callout drivers using C++ or C#.

• Core Networking Engine Integration
  Enhance and optimize the platform’s high performance networking engine written in Go, ensuring reliable interoperability with platform specific system hooks.

• Interprocess Communication and Service Orchestration
  Design and implement secure IPC mechanisms to connect privileged services with user space applications, including:

  • XPC on macOS
  • ALPC, Named Pipes, or gRPC on Windows

• Performance Optimization
  Diagnose and resolve networking performance issues including packet path bottlenecks, memory leaks in long running services, and operating system specific connectivity edge cases.

How You Will Work

• Subject Matter Expert (SME)
  Serve as a system-level networking specialist with deep knowledge of Windows and macOS networking APIs, operating with minimal ramp-up or oversight.

• Hands-On Development
  Spend ~80–90% of your time actively contributing to the codebase, translating architectural requirements into production-ready implementations.

• Technical Quality and Standards
  Follow our company's engineering standards for memory safety, concurrency management, code quality, and documentation to ensure maintainability beyond the contract period.

3. Key Responsibilities

Platform Implementation

• Delivering feature-complete implementations for:

  • macOS NEPacketTunnelProvider (Swift)
  • Windows WFP callout drivers (C++)

• Integrate platform-specific networking logic with shared Go services.

Cross-Language Integration

• Implement and maintain safe interoperability between Go and platform-specific system code using cgo.
• Ensure reliable and efficient data exchange across language boundaries.

System Reliability

• Troubleshoot and resolve OS-level networking challenges including:
  • Sleep and wake reconnection logic
  • DNS interception conflicts
  • VPN kill-switch enforcement
  • Long running daemon stability

Release Readiness

• Manage platform-specific release requirements including:
  • Windows EV Code Signing
  • Apple Notarization
  • Entitlements and security provisioning

4. Documentation & Knowledge Transfer

Technical Documentation

• Produce detailed documentation covering:
  • IPC protocols
  • System architecture changes
  • State machines and threading models introduced during the engagement

Engineering Handover

• Provide clear pull request documentation and structured knowledge transfer sessions to ensure permanent engineering staff can maintain and extend delivered components.

5. Ideal Experience

• Extensive experience with system-level networking development on Windows and macOS
• Strong proficiency in Swift, C++, C#, and Go
• Deep familiarity with macOS NetworkExtension framework and Windows Filtering Platform
• Experience designing and implementing secure interprocess communication mechanisms
• Strong debugging and performance tuning skills in system-level networking environments
• Experience working within production-grade security or networking software
• Ability to deliver high-quality code in a fast moving, project-based environment