Principal Software Engineer

Microsoft • Redmond, WA

4d

About The Position

The Windows App for the web is a full Windows client implemented inside a browser runtime. It powers Azure Virtual Desktop and Windows 365 by translating operating system expectations—graphics, input, media, identity, security and device access—into something that can execute reliably inside modern web platforms, bringing a “like-local” Windows experience to millions of enterprise users.
We’re seeking a Principal Software Engineer to operate in the foundational layers of our web client, where architectural decisions directly affect performance, reliability, security posture, and long-term evolution. This role serves as a technical anchor for the client, with hands-on work spanning rendering and graphics pipelines, protocol stacks, WebAssembly-based components, media and device redirection, authentication, telemetry, and the isolation boundaries that allow a browser to behave like a high-fidelity Windows endpoint.
At this level, impact comes from working on the hardest parts of the stack while providing technical clarity through design choices and trade-offs, shaping how the system is built, integrated, and evolves as browser capabilities, cloud infrastructure, and Windows workloads continue to converge.
We’re a collaborative, high-energy group that values curiosity, craftsmanship, and a growth mindset.
What is Windows App: https://learn.microsoft.com/en-us/windows-app/overview
Video: https://youtu.be/j0XU59VbKOc
Why this problem space matters
This work defines how Windows runs when the browser is the platform. The solutions ship at global scale and are constrained by real-world networks, devices, and security models. For engineers who enjoy working close to the limits of what the web runtime allows—and extending it responsibly—this is a rare problem space.
What you’ll work on
You’ll operate primarily in the foundational layers of the client, where performance, correctness, and constraints are explicit:
Rendering and interaction pipelines
High-performance remote graphics using Canvas, WebGL/WebGPU, and WebAssembly
Input fidelity across keyboard, mouse, touch, pen, and specialized devices
Latency control, frame pacing, bandwidth adaptation, and GPU utilization
Client protocol and transport architecture
Design and evolution of remoting protocols optimized for web runtimes
Reliability, congestion control, and session resilience across heterogeneous networks
Tight coordination between browser client, gateways, and cloud services
WebAssembly and native code integration
Performance-critical C/C++ components compiled to WASM
Memory models, threading, SIMD, and sandbox constraints
Deep integration with Chromium APIs and browser execution models
Media and device redirection
Audio/video pipelines supporting Teams optimization and real-time collaboration
Multimedia redirection with strict latency and synchronization requirements
Device and peripheral redirection (e.g., smart cards, cameras, microphones) mapped into web-safe abstractions
Identity, security, and isolation
Smart card redirection, WebAuthn/FIDO flows, and authentication pass-through
Clear trust boundaries between local device, browser, and remote session
Secure-by-design client architectures that preserve performance and usability
Microsoft’s mission is to empower every person and every organization on the planet to achieve more. As employees we come together with a growth mindset, innovate to empower others, and collaborate to realize our shared goals. Each day we build on our values of respect, integrity, and accountability to create a culture of inclusion where everyone can thrive at work and beyond.

Requirements

• Bachelor’s in Computer Science or related field AND 6+ years of technical engineering experience including web technologies and browser APIs and full-stack product engineering with coding in languages like C, C++, JavaScript
• Ability to meet Microsoft, customer and/or government security screening requirements are required for this role.
• Microsoft Cloud Background Check: This position will be required to pass the Microsoft Cloud background check upon hire/transfer and every two years thereafter.

Nice To Haves

• Hands-on experience with remote desktop protocols (RDP), graphics PDUs, or virtual channels.
• Exposure to live site engineering practices, telemetry pipelines, and monitoring systems.
• Ability to work across the stack and contribute to both frontend (React, TypeScript) and backend (C++, services) components.
• Strong problem-solving skills and a growth mindset with a willingness to learn and mentor others.
• Experience working in agile teams with short, iterative release cycles and a DevOps culture.

Responsibilities

• Define and drive end-to-end designs spanning browser, protocol, and cloud
• Make architectural calls under real constraints imposed by browsers and security models
• Identify performance ceilings and systematically remove them
• Partner across Windows, Chromium, Teams, and Azure to align deep technical decisions
• Raise the technical bar through design reviews, mentorship, and examples.

What This Job Offers

• Job Type: Full-time
• Career Level: Mid Level