Senior Staff Performance Engineer, Firefox
Mozilla
Hirezar Summary for South African Applicants
This fully remote full time position at Mozilla is open worldwide, so South Africans can apply. As a remote position, you can work from anywhere in South Africa — whether you're based in Johannesburg, Cape Town, Durban, or a smaller town.
Job Description
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<p style="text-align: justify; line-height: 1;">To learn more about our Hiring Range System, please click this <a href="https://docs.google.com/document/d/1ylUe7Ou0EbsOtGRBtUv1sSld3lbZ4mrYzo59tEkSjY8/edit?usp=sharing" target="_blank"><span style="text-decoration: underline;"><strong>link.</strong></span></a></p>
<p><strong>Why Mozilla?</strong></p>
<p><span style="font-weight: 400;">Mozilla Corporation is the non-profit-backed technology company that has shaped the internet for the better over the last 25 years. We make pioneering brands like Firefox, the privacy-minded web browser. Now, with more than 225 million people around the world using our products each month, we’re shaping the next 25 years of technology and helping to reclaim an internet built for people, not companies. Our work focuses on diverse areas including AI, social media, security and more. And we’re doing this while never losing our focus on our core mission – to make the internet better for people. </span></p>
<p><span style="font-weight: 400;">The Mozilla Corporation is wholly owned by the non-profit 501(c) Mozilla Foundation. This means we aren’t beholden to any shareholders — only to our mission. Along with thousands of volunteer contributors and collaborators all over the world, Mozillians design, build and distribute </span><strong>open-source</strong><span style="font-weight: 400;"> software that enables people to enjoy the internet on their terms. </span></p>
<p><strong>About this team and role:</strong></p>
<p><span style="font-weight: 400;">The Mozilla Firefox Performance team is a community of engineers who care deeply about delivering the fastest browser possible. We are the team responsible for making all parts of the browser go fast.</span></p>
<p><span style="font-weight: 400;">Our team is geographically-distributed, and working in the open is the norm. We contribute to the code driving the Firefox browser on a number of platforms - Windows, Android, Linux, and macOS. Our focus is on finding and fixing things that slow down the browser as well as helping other teams write fast and reliable code to make Firefox excellent for users.</span></p>
<p><span style="font-weight: 400;">Do you value curiosity and enjoy finding a needle in a haystack? Do you approach problems by looking at the system as a whole? Do you want to help lead and shape the future of the Internet? Do you like making things blazingly fast? If so, we’d love to hear from you.</span></p>
<strong>What you'll do:</strong>
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<li style="font-weight: 400;"><span style="font-weight: 400;">Write code and tests, build prototypes, tackle problems, profile and analyze performance bottlenecks</span></li>
<li style="font-weight: 400;"><span style="font-weight: 400;">Learn about a wide variety of problems and solutions across a large, complex, and evolving codebase</span></li>
<li style="font-weight: 400;"><span style="font-weight: 400;">Use several programming languages (e.g., C++, JavaScript, Kotlin, Rust, Python) and techniques to fix performance issues, with an emphasis on C++ and JavaScript</span></li>
<li style="font-weight: 400;"><span style="font-weight: 400;">Help to educate engineers on other teams about writing more performant code through code reviews, giving talks, implementing tooling, and/or writing documentation</span></li>
<li style="font-weight: 400;"><span style="font-weight: 400;">Independently define and drive actionable next steps from high level objectives</span></li>
<li style="font-weight: 400;"><span style="font-weight: 400;">Work with engineering teams across the organization to assist and lead performance efforts</span></li>
<li style="font-weight: 400;"><span style="font-weight: 400;">Shape the future of performance benchmarks, and set the proper priorities for the necessary improvements</span></li>
<li style="font-weight: 400;"><span style="font-weight: 400;">Develop strategies for the future of the Performance team and the Organization as a whole</span></li>
<li style="font-weight: 400;"><span style="font-weight: 400;">Work with driven, committed team members to help bring the Open Web to millions of people </span></li>
</ul>
<strong>What you'll bring:</strong>
<ul>
<li style="font-weight: 400;"><span style="font-weight: 400;">BS/MS in CS, CE and 7+ years relevant experience</span></li>
<li style="font-weight: 400;"><span style="font-weight: 400;">A mastered understanding of programming in C++</span></li>
<li style="font-weight: 400;"><span style="font-weight: 400;">An understanding of programming in JavaScript</span></li>
<li style="font-weight: 400;"><span style="font-weight: 400;">You have proven experience developing performance critical software</span></li>
<li style="font-weight: 400;"><span style="font-weight: 400;">You
Tips for South African Applicants
Timezone Advantage
South Africa (SAST, UTC+2) overlaps well with European business hours and has a few hours of overlap with US East Coast. Mention your timezone flexibility in your application.
Salary in Context
Even without a listed salary, international remote roles typically pay 2-3x more than equivalent local positions in South Africa due to the exchange rate advantage.
Application Tips
Tailor your CV to international standards — use a clean format, highlight remote work experience, and include your English proficiency. Many SA applicants succeed by emphasising their strong work ethic and cultural adaptability.
Load Shedding Preparedness
If you're applying for a remote role, having a backup power solution (UPS, inverter, or generator) and mobile data as a backup internet connection shows employers you're prepared for South Africa's infrastructure challenges.
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About Mozilla
Mozilla is a company in the Firefox industry that hires remote workers from South Africa. They currently have 26 open positions on Hirezar. View all Mozilla jobs →