Senior Unix Engineer Jobs in Ontario (NOW HIRING)

Build High-Performance Enterprise Software as a Senior C++ Developer! 

We're partnering with a well-established software company that develops enterprise security products trusted by organizations where reliability, performance, and data protection are essential. They're seeking a Senior C++ Software Developer to help modernize core applications, build new enterprise software capabilities, and contribute to solutions that support secure, high-availability environments.  

This is an opportunity to work on technically sophisticated software where performance, security, and uptime are critical. You'll help evolve long-standing enterprise products, develop new functionality supporting security and audit requirements, and solve complex engineering challenges across modern and legacy platforms. 

 Who You Are 

You are a senior software engineer who enjoys building reliable, scalable, and highly performant applications. 

You thrive in environments where software quality, architecture, and security are equally important, and you're comfortable diving deep into operating system internals, networking, multithreading, and performance optimization. 

You're someone who enjoys modernizing legacy systems, mentoring technical discussions, and solving complex engineering problems while maintaining a strong focus on clean, maintainable code. 

Most importantly, you enjoy building software that powers business-critical systems where stability, uptime, and security matter every single day. 

Work Type 

Location: Mississauga, ON 
Hybrid: 3 days per week in office  
Vacancy Type: This position reflects a new vacancy 

Requirements

What You'll Do 

• Design, develop, and support high-performance enterprise applications using modern C++ within complex, mission-critical environments 
• Modernize existing client-server applications by introducing modern APIs and new methods of application integration 
• Develop new enterprise software supporting critical data security, auditing, and compliance solutions for enterprise customers 
• Architect scalable software components that operate across enterprise operating environments 
• Write clean, maintainable, and efficient C++ code following modern software engineering best practices 
• Optimize application performance through advanced profiling, memory analysis, multithreading optimization, and bottleneck identification 
• Work closely with UNIX/Linux operating systems, system APIs, networking stacks, and low-level communication protocols 
• Implement secure coding practices including encryption, vulnerability mitigation, and application security controls 
• Participate in source control management, code reviews, branching strategies, and collaborative development using Git 
• Develop and maintain integrations with enterprise database technologies and high-availability transaction processing environments 
• Troubleshoot complex production issues and support highly available enterprise software platforms 
• Collaborate with cross-functional engineering teams throughout design, development, testing, and deployment activities 
• Maintain technical documentation, development standards, and software design artifacts 
• Continuously identify opportunities to improve application performance, scalability, maintainability, and security 

What We're Looking For 

• 10+ years of professional experience developing enterprise software applications using C++ 
• Expert-level knowledge of modern C++, object-oriented design principles, and software architecture 
• Strong experience building multithreaded, high-performance applications 
• Deep understanding of memory management, debugging techniques, profiling tools, and performance optimization 
• Strong experience working within UNIX and Linux operating environments 
• Hands-on experience with system APIs, shell scripting, and TCP/IP networking concepts 
• Strong understanding of secure software development, encryption standards, vulnerability management, and secure coding practices 
• Experience using Git, modern version control workflows, code reviews, and collaborative development methodologies 
• Experience working with C/C++ build systems, compilers, linkers, and Makefiles 
• Experience developing enterprise applications that require high availability, reliability, and scalability 
• Strong analytical, troubleshooting, and problem-solving skills 
• Excellent communication skills with the ability to collaborate across technical teams 

Nice-to-Have 

• Experience working with HPE NonStop (Tandem) environments  
• Java or other enterprise backend development experience  
• Experience with SQL/MX, SQL/MP, or similar enterprise database technologies  
• Exposure to embedded systems or hardware/software integration  
• Experience developing software for banking, financial services, telecommunications, or other high-availability enterprise environments 

What Makes This Role Exciting 

• Build Software That Matters: Develop enterprise applications supporting mission-critical systems relied upon by international organizations. 
• Solve Complex Engineering Challenges: Work on advanced C++ development, multithreading, networking, performance optimization, and secure software design. 
• Modernize Enterprise Platforms: Help transform legacy applications into modern, scalable solutions while influencing long-term architecture. 
• Security-First Development: Play a key role in building secure software through encryption, vulnerability management, and industry best practices. 

Benefits

• Base Salary: $110,000 - $130,000 
• Paid Time Off: Competitive vacation and personal days to help maintain a healthy work-life balance 
• Health & Wellness Benefits: Medical, dental, and vision benefits to support your overall well-being    

 Ready to Elevate Your Career? Apply Now!   

At STACK IT Recruitment, we connect top talent with standout opportunities. If you meet at least 70% of the qualifications, we encourage you to apply for it. We'd love to chat!   

Know someone perfect for this role?Share this with your network, you might just help someone take the next big step in their career.   

 We're proud to support diversity and inclusion. Need accommodation during the hiring process? Just let us know; we are here to support you!  

AI Use Disclosure:   

STACK IT uses AI-enhanced tools to support initial candidate screening and interview note analysis. All assessments and hiring decisions remain human-led.