Principal Software Development Engineer in Test (macOS) in Tallinn at Malwarebytes Inc.

Here at Malwarebytes, we believe that when you’re free from threats, you’re free to thrive. It all started in 2008 with one person who needed help with a malware infection, and a community coming together to find solutions. In that moment in time a product was born for all people, with a mission to rid the world of malware. Our product has since grown and evolved, from removing malware, to protecting devices, to ever-changing prevention.

About Malwarebytes Inc.

Malwarebytes began after our founder, Marcin Kleczynski, accidentally infected his parents’ computer while downloading a video game as a teenager. At the time, there was no product that could fully solve the problem, so he set out to build one. That early experience shaped our mission: to create protection that works when people need it most.
Since then, the digital threat landscape has only grown more complex. Attackers are faster, stealthier, and more sophisticated, while traditional solutions often overwhelm people with complicated tools and settings. At Malwarebytes, we believe protection should be both powerful and refreshingly simple because if security feels too hard to use, people will not use it. That is why our aspiration is always to stay one step ahead: cutting through the noise, stopping threats others miss, and delivering peace of mind in an unpredictable digital world.

About ThreatDown

ThreatDown, the corporate business unit of Malwarebytes, is redefining cybersecurity for growing businesses with solutions that stop ransomware, malware, phishing, and AI-powered attacks. Our platform is trusted, intuitive, and built for lean IT teams that need speed without complexity. At ThreatDown, you’ll join a team driven by innovation, resilience, and a passion for empowering businesses to thrive securely. If you're ready to make a real impact in cybersecurity, we’d love to meet you.

ThreatDown is looking for..

ThreatDown is looking for an experienced Mac Automation Quality Engineer with a strong background in endpoint security and macOS platform testing. This role is ideal for someone who thrives in a fast-paced, multi-product environment, enjoys building scalable automation frameworks, and has a passion for uncovering complex platform and security-related issues. You’ll work closely with Engineering, Product Management, and Security teams to ensure high-quality delivery across modern macOS environments, while working on cutting-edge endpoint security technologies, helping secure enterprise environments at scale, collaborating with highly technical engineering and security teams, influencing automation strategy and quality practices across multiple products, and gaining deep exposure to the macOS security ecosystem and Apple Silicon platforms.

What You Will Do:

• Design, develop, and maintain automated test suites using Python and PyTest
• Validate endpoint security functionality across macOS releases and Apple Silicon platforms
• Debug and troubleshoot macOS-specific issues related to system behavior, sandboxing, permissions, and performance
• Analyze logs and diagnostics using macOS tools such as Console, sysdiagnose, and spindump
• Collaborate closely with developers to isolate issues, validate fixes, and ensure compatibility with new macOS versions
• Build and maintain test environments across physical Macs and virtualized macOS infrastructure
• Execute and enhance automated and manual test coverage for endpoint security features
• Track, document, and prioritize defects with clear reproduction steps and analysis
• Drive improvements in automation coverage, regression stability, execution efficiency, and quality metrics
• Participate actively in Agile development processes and continuously improve QA methodologies and tooling

Skills You'll Need to Have:

• 5+ years of experience in Quality Engineering, Test Automation, or Software Validation
• Strong experience testing macOS applications or endpoint security products
• Deep understanding of macOS internals, logging, and diagnostic tooling
• Hands-on experience with Python, PyTest, Bash scripting, and Git
• Experience with CI/CD and build systems such as Azure DevOps, Jenkins, GitLab, or TeamCity
• Experience with macOS virtualization platforms including VMware, UTM, or Tart
• Strong analytical, debugging, and troubleshooting skills
• Excellent written and verbal communication skills

Skills that are Nice to Have:

• Experience with Apple Endpoint Security Framework (ESF), MDM platforms, or mobileconfig profiles
• Experience testing EDR, antivirus, or endpoint protection technologies
• Familiarity with CI/CD automation pipelines and infrastructure testing
• Networking knowledge including REST APIs, TCP/IP, DNS, DHCP, and Active Directory
• Linux/Unix administration experience
• Enterprise IT administration experience including software deployment, security policies, backups, and multi-user environments
• Strong object-oriented programming fundamentals

Perks & Benefit:

• An opportunity to do something great for yourself and the world!

• Employee Referral Bonus Program 

• Wellness programs  

(Benefits and Perks subject to change by country/region)