Performance Engineer - Open Source

This position is listed on behalf of a partner company, who manages all applications and next steps. Our partner is looking for a Performance Engineer - Open Source based in Romania.

This role is designed for an exceptional engineer focused on improving software performance, correctness, scalability, and efficiency across the technology stack.

You will work across open source systems ranging from low-level infrastructure and kernels to runtimes, databases, applications, and web technologies.

The position combines deep technical investigation with hands-on engineering, allowing you to identify bottlenecks and develop meaningful performance improvements.

You will contribute to shared tooling, measurement frameworks, dashboards, test harnesses, and analytical capabilities that raise engineering standards across teams.

Beyond individual technical contributions, you will help build a strong performance culture through mentorship, training, technical leadership, and knowledge sharing.

The role offers exposure to diverse architectures, CPUs, cloud platforms, and software environments while collaborating with engineers and communities around the world.

It is particularly suited to a rigorous, curious engineer who enjoys solving complex systems problems and using data-driven insights to improve both performance and correctness.

Accountabilities:

• Drive software performance, scalability, efficiency, and correctness within a specific engineering project.
• Analyze systems and code across the stack to identify performance bottlenecks, scalability limitations, and opportunities for optimization.
• Collaborate with engineering teams and open source communities globally to investigate and resolve complex technical challenges.
• Develop and contribute to shared tools and infrastructure for performance measurement, profiling, analysis, benchmarking, and reporting.
• Strengthen testing capabilities, test harnesses, and engineering pipelines to make previously difficult-to-measure system behaviors observable and verifiable.
• Establish and promote effective performance engineering practices, measurement frameworks, and analytical approaches.
• Teach, train, mentor, and develop colleagues to strengthen performance-focused engineering skills and culture.
• Solve technical problems directly while also influencing teams through technical leadership, knowledge sharing, and skills development.
• Review code and technical designs with a focus on performance, efficiency, scalability, and correctness.
• Contribute to performance optimization across different hardware architectures, CPUs, cloud environments, runtimes, and system components.
• Share insights, tools, and best practices that can improve performance engineering across a broader range of products and engineering teams.

Requirements:

• Exceptional academic track record at both high school and university level.
• Undergraduate degree in Computer Science, Mathematics, Physics, or a comparable technical discipline.
• Demonstrable personal initiatives or professional experience focused on improving software performance, efficiency, scalability, or correctness.
• Strong experience with Linux, with Debian or Ubuntu experience preferred.
• Ability to understand complex systems deeply and investigate performance across multiple layers of the technology stack.
• Professional written and spoken English with strong presentation and communication skills.
• Confidence to respectfully challenge ideas, exchange feedback, and communicate technical perspectives openly.
• Proven ability to deliver outstanding results and take ownership of challenging engineering problems.
• Leadership mindset with a commitment to mentoring colleagues and developing technical skills within a team.
• Strong passion for technology, demonstrated through personal projects, open source contributions, or other initiatives.
• Excellent interpersonal skills, curiosity, flexibility, accountability, and self-motivation.
• Results-oriented approach with a strong personal drive to meet commitments and continuously improve.
• Comfortable working effectively within multicultural, multinational, globally distributed teams.
• Ability to travel internationally twice per year for company events lasting up to two weeks.

Nice-to-have technical expertise includes:

• Low-level CPU architecture and assembly language, including caches, registers, vectorization, and memory behavior.
• Kernel performance, including scheduling, context switching, and hardware acceleration.
• Distributed systems performance, tracing, and debugging.
• Compiler-level optimization, including profile-guided optimization, inlining, and assembly analysis.
• Runtime performance across technologies such as Golang, Python, JVM, and Node.js.
• Database performance evaluation involving query plans, indexing, data modeling, tracing, and monitoring.
• Web browser and web application performance, including JavaScript, web frameworks, tracing, and CSS.
• Performance measurement and profiling tools such as eBPF, D-Trace, and flamegraphs.
• Benchmarking tools such as the Phoronix Test Suite.
• Test harness development using C, C++, Rust, Python, Golang, Node.js, or JavaScript.

Benefits:

• Performance-driven annual bonus or commission in addition to base compensation.
• Compensation reviewed based on geographical location, experience, and performance.
• Annual compensation review with more frequent reviews where appropriate for graduates and associates.
• Fully distributed work environment with twice-yearly in-person team sprints.
• USD 2,000 annual personal learning and development budget.
• Recognition and performance rewards.
• Annual holiday leave.
• Maternity and paternity leave.
• Employee Assistance Programme.
• Opportunities to travel to new locations and meet colleagues from around the world.
• Priority Pass access and travel upgrades for eligible long-haul company events.
• Opportunity to work across a broad open source technology stack and collaborate with globally distributed engineering teams.