Senior Windows Endpoint Systems Engineer (C# / C++)
First seen by Alion on Nov 9, 2026.
Our Customer:
Our customer is an international product company that builds enterprise software for monitoring and managing large fleets of corporate devices. Its products help IT teams keep workplace endpoints stable, secure and performing well at scale.
Your Tasks:
Build the low-level layer that observes the operating system, in both managed and native code
Keep the agent’s resource footprint minimal so that end users never notice it
Ensure reliable and secure endpoint-to-cloud communication, including on unstable networks and during offline operation
Implement endpoint actions that change device state safely, predictably and with a clear audit trail
Extend on-device detection to automatically identify and investigate known issues
Build the on-device user experience presented by the agent
Own agent installation, upgrades and rollbacks across very large device fleets
Diagnose field failures, including conflicts with endpoint security products
Turn architectural direction into complete, production-quality implementations with minimal supervision
Required Experience and Skills:
6+ years of experience building production software focused on Windows systems, endpoint agents or long-running unattended software
Deep understanding of Windows internals, including processes, threads, memory, sessions, services, tokens, privileges and the Windows security model
Strong command of C# and .NET
Solid production experience with C++
Hands-on experience with managed-to-native interoperability
Hands-on experience with native Windows interfaces, including Win32, ETW, WMI and performance counters
Proven ability to profile and optimize CPU, memory and I/O usage for continuously running, low-footprint software
Hands-on experience with root-cause analysis using crash dumps and traces
Solid understanding of concurrency in long-running software
Proven ability to build reliable, self-recovering software
Hands-on experience delivering, signing and upgrading software at fleet scale
Strong security discipline when developing software that runs with elevated privileges
Hands-on production experience with AI-assisted and agentic coding tools
Proven ability to critically review AI-generated code
English – Advanced
Would Be a Plus:
Production experience with Swift
Hands-on experience with macOS systems programming, including launchd daemons, XPC, system extensions, privacy controls and notarization