This job posting is for an existing, active vacancy and we are looking to hire Sr. Windows API & Browser Extension Developer at Brampton, ON (100% onsite).

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Role Overview

We are seeking an experienced Senior Windows API & Browser Extension Developer to design, develop, and implement a secure Windows-based integration solution for a standalone enterprise environment. The solution will capture user-submitted data from a web portal through a Microsoft Edge browser extension and securely integrate it with downstream REST APIs using Windows Native Messaging or a locally hosted Windows service.

The role requires hands-on experience in Windows application development, browser extension development, API integration, security engineering, and enterprise-grade software delivery.

Key Responsibilities – Senior Windows API & Edge Extension Developer

- Design, develop, and deploy a secure Microsoft Edge (Chromium) browser extension for automated data capture and API integration workflows.
- Develop Windows-based integration components using C#, .NET Core, Windows Services, Win32 APIs, and Windows Native Messaging.
- Build and integrate secure REST APIs with support for API Keys, TLS/mTLS, certificate-based authentication, and secure communications.
- Design solutions to process sensitive business data entirely in memory, ensuring no transaction data is written to disk, logs, or diagnostic files.
- Implement robust error handling, retry mechanisms, timeout controls, status tracking, and resilience patterns for API interactions.
- Develop and support multi-user Windows Server / Terminal Services environments supporting concurrent user sessions.
- Configure and manage Windows security components including Certificate Store, DPAPI,



service accounts, access controls, and secure secret management.
- Perform unit testing, integration testing, API testing, browser extension testing, and end-to-end system validation.
- Ensure compliance with Secure SDLC, secure coding standards, vulnerability scanning, code reviews, and security remediation requirements.
- Create and maintain HLD, LLD, deployment guides, operational runbooks, support documentation, and knowledge transfer materials.
- Collaborate with customer architects, security teams, infrastructure teams, and project stakeholders throughout the project lifecycle.
- Support deployment, production stabilization, warranty support, troubleshooting, and defect resolution activities.
- Package and deliver signed release artifacts, installation binaries, and deployment documentation for Windows Server environments.

Mandatory Skills

- Windows Server 2019/2022 Administration & Development (Mandatory)
- Windows Terminal Services (RDS) Environment Management
- C#, .NET Core / ASP.NET Core
- Windows API / Win32 Development
- Microsoft Edge Extension Development (Manifest V3)
- Windows Native Messaging
- REST API Development & Integration
- TLS / mTLS / Certificate Management
- Windows Security, DPAPI, Certificate Store
- Secure SDLC & OWASP Secure Coding
- Git/GitHub, CI/CD and Release Management
- Unit, Integration and End-to-End Testing

Experience

- 8+ years of Software Development experience.
- 5+ years of Windows Server, Windows Platform and .NET Development.
- 3+ years of Browser Extension and API Integration Development.
- Experience delivering secure enterprise solutions in Windows Server environments.
- Robust troubleshooting, documentation, and customer-facing communication skills.

📌 Sr. Windows API & Browser Extension Developer (Brampton)
🏢 TechDoQuest
📍 Brampton