Senior Windows Engineer

Ambition; Hong Kong; On-site; HKD 600,000 - 1,000,000; Full time

Job summary

Ambition is seeking an elite Windows Systems Engineer to own, optimize, and scale its core Windows infrastructure. You will dive deep into OS internals, ensuring a high-throughput, low-latency environment operates at peak reliability across a global footprint.

You will build centralized automation in PowerShell, Python, or C# and collaborate with global teams to plan deployments, troubleshoot deep-level failures, and maintain advanced infrastructure documentation.

Qualifications

• Deep expertise in Windows 10/11 and Windows Server (2016/2019/2022) internals.
• Thorough understanding of TCP/IP/UDP, NIC teaming, RSS, and interrupt moderation.
• Experience with Active Directory, Kerberos, DNS, Group Policy and OS-level troubleshooting.

Responsibilities

• Own and optimize Windows kernel behaviors for low latency workloads.
• Diagnose memory bottlenecks and manage virtual memory and paging.
• Manage Windows I/O subsystem, IRPs, and async vs sync I/O pipelines.

Skills

Windows Internals Mastery

Advanced Networking Stack

Windows Security Architecture

Core Services & Diagnostics

Hardware & Virtualization Tuning

Execution & Communication

Tools

PowerShell

Python

C#

Job description

We are seeking an elite Windows Systems Engineer to own, optimize, and scale our core internal Windows infrastructure. In this role, you will move far beyond surface-level administration, diving deep into the operating system's internals to ensure our high-throughput, low-latency environment operates at peak performance and reliability.

Windows serves as our primary desktop ecosystem, and our critical core backend infrastructure relies heavily on Windows Server instances. You will be responsible for the architectural health, deep-system troubleshooting, and programmatic automation of this global footprint.

This position sits within an engineering-first culture where manual intervention is treated as technical debt. You will build, code, and review centralized, version-controlled automation frameworks using PowerShell, Python, or C# to manage a physical and virtual compute landscape across a high-performance global network.

Key Responsibilities

• Performance Engineering: Analyze and optimize Windows kernel behaviors, evaluating process and thread dynamics, managing thread pools, tuning I/O Completion Ports (IOCPs), and configuring thread priorities and processor affinity for latency-critical workloads.
• Memory Optimization: Diagnose complex memory bottlenecks, managing virtual memory allocation, paging mechanisms, and working sets. You will systematically debug discrepancies between private bytes, working set sizes, and commit sizes, utilizing memory-mapped files for high-efficiency data persistence.
• Subsystem Management: Maintain the stability of the Windows I/O subsystem. You will trace I/O Request Packets (IRPs), optimize synchronous vs. asynchronous (overlapped) I/O pipelines, and manage low-level system resources.
• Infrastructure Automation: Engineer and maintain scalable, peer-reviewed automation tools written in PowerShell, Python, or C#. All scripts are centrally managed in an organized repository to ensure consistency across all regional infrastructure nodes.
• Global Collaboration: Partner with global engineering teams to plan major deployments, diagnose deep-level system failures, and maintain highly technical infrastructure documentation.

About You

We are looking for an engineer with an elite understanding of the Microsoft Windows ecosystem. While we value a continuous learning mindset, you will ideally bring deep subject matter expertise in the following areas:

• Windows Internals Mastery: Advanced experience with the inner workings of Windows 10/11 and Windows Server (2016/2019/2022), specifically understanding Kernel vs. User Mode transitions, the precise performance cost of context switches, and structural registry performance (hives, cells, and memory caching).
• Advanced Networking Stack: Thorough understanding of the complete path of a network packet from the physical NIC to the user-mode socket. Experience tuning TCP/IP and UDP configurations, window sizing, NIC teaming, Receive Side Scaling (RSS), and interrupt moderation.
• Windows Security Architecture: Practical command of the Windows security subsystem, including access tokens, security descriptors (DACLs, SACLs), user privileges, and integrity levels.
• Core Services & Diagnostics: Proficient working knowledge of enterprise infrastructure services (Active Directory, Kerberos, DNS, Group Policy), alongside a demonstrated ability to systematically troubleshoot OS-level deadlocks, crashes, and resource starvation.
• Hardware & Virtualization Tuning: Experience analyzing hardware monitoring metrics and performing fine-grained tuning across physical bare-metal and virtualized computing landscapes.
• Execution & Communication: Clear, concise communication skills, a highly collaborative approach, and the capability to solve complex architectural problems in a fast-paced, high-stakes environment.