Source Job

Canada

  • Write code and tests, build prototypes, and profile performance bottlenecks across a large codebase.
  • Use multiple programming languages including C++ and JavaScript to fix performance issues and educate other teams.
  • Independently define and drive performance strategies, shaping benchmarks and priorities for the team and organization.

C++ JavaScript Performance Analysis Debugging Profiling

20 jobs similar to Senior Staff Performance Engineer, Firefox

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$5,925–$9,250/mo
Europe 4w PTO

  • Developing and maintaining core technology systems on Unreal Engine for a large open-world game.
  • Proposing and implementing solutions for performance and scale challenges.
  • Collaborating across disciplines and with Epic Games to push technology forward.

We create revolutionary, story-driven RPGs that go straight to the hearts of gamers. With a team of passionate developers, we foster a collaborative and inclusive culture, offering extensive benefits and support for professional growth.

LATAM

  • Design and implement high-performance components in Rust, C++, or Go for the DEX engine and protocol runtime.
  • Build low-latency pipelines for order execution, event propagation, and state updates, optimizing concurrency and memory layout.
  • Investigate and resolve performance bottlenecks using profiling and benchmarking, driving system design decisions for senior candidates.

Nexus is the engine for verifiable finance, building a blockchain designed to embed the global financial system into one compounding system. Headquartered in San Francisco with a growing presence in Buenos Aires, the cross-continental team is backed by leading investors and works with more than 100 partners.

US

  • Provide technical leadership across core subsystems of the simulation platform.
  • Drive architectural decisions and champion modern engineering practices.
  • Lead delivery of complex features and safeguard long-term codebase health.

Datacor is a leading provider of software solutions for the process manufacturing industry, including ERP, CRM, and simulation tools. The company is passionate about serving customers and leveraging data as a competitive advantage, with a focus on building thoughtful, intuitive products.

US

  • Design, develop, and execute performance testing scenarios including load, stress, spike, and scalability tests.
  • Investigate application performance issues by analyzing application, infrastructure, and database bottlenecks.
  • Integrate performance testing into CI/CD pipelines and apply AI/ML techniques to improve test automation.

The company is a partner organization focused on healthcare technology, providing enterprise-scale applications. It operates with a collaborative, inclusive remote engineering culture and values diversity.

$100,000–$120,000/yr
US

  • Expanding core AI and M&S frameworks to support new domains and use cases.
  • Integrating software with other systems and supporting varied computing environments.
  • Designing new features, implementing C++ changes, and working closely with front-end and third-party developers.

STILMAN Advanced Strategies develops software based on Linguistic Geometry, a unique AI approach for military mission planning and execution. Our small, distributed team has been developing these applications since 1999, focusing on quality and collaboration.

US

  • Enhance and maintain in-house synthetic data generation tools.
  • Investigate performance issues and develop performance test scripts.
  • Integrate performance testing into CI/CD pipelines and collaborate with cross-functional teams.

HealthEdge provides AI-powered operational infrastructure for health insurance companies to gain an enduring financial edge. The company is experiencing strong market momentum, investing in its people as it expands in the healthcare technology space.

Global

  • Drive initiatives to deliver high-quality, maintainable software for Firefox Desktop user experience.
  • Communicate team goals, manage trade-offs, and own delivery of projects on clear timelines.
  • Engage with team members through 1-1s, provide feedback, and create an inclusive environment.

Mozilla Corporation is a non-profit-backed technology company that has shaped the internet for the better over the last 25 years, creating brands like Firefox. With over 225 million monthly users, the company is mission-driven and focused on building an internet that serves people, not shareholders.

Canada

  • Drive the technical direction and execution of a new original game developed in Unreal Engine 5, establishing pipelines and workflows for engineering and art.
  • Lead engineering efforts across core gameplay systems, AI, platform support, and build/delivery pipelines to deliver a polished, performant, and fun experience.
  • Mentor engineers, set best practices, and collaborate with technical leadership to align engineering execution with project goals and production timelines.

Blackbird Interactive is an independent game studio working on world-class IPs and original creations across multiple genres. They operate as a remote-first workplace with a focus on long-term career growth and flexible work arrangements.

North America

  • Manage, mentor, and grow a team of game engineers, setting goals and refining team processes.
  • Debug complex multiplayer systems, review code, and prototype gameplay systems.
  • Partner with design, art, and production to align engineering with creative vision.

Gardens Interactive is a fully distributed game studio building multiplayer fantasy adventures centered on connection and emergent stories. Founded by creators behind titles like Journey and Baldur's Gate 3, they foster a collaborative, high-trust culture with a lean team focused on curiosity and mutual support.

$90,000–$105,000/yr
Canada

  • You'll collaborate with game designers to build engaging gameplay experiences for a massively multiplayer online game.
  • You'll develop and test code for new systems and augment existing systems in a live-service environment.
  • You'll participate in code reviews, document systems, and provide reliable time estimates for tasks.

Ravenwake Games is the newest studio within Enad Global 7, a global leader in video game development and publishing. The studio is committed to crafting immersive worlds that bring players together and deliver unforgettable gameplay.

Europe Israel

  • Design and build large-scale rendering systems for modern web applications.
  • Develop browser-based rendering infrastructure for reliable JavaScript execution.
  • Optimize rendering cost, latency, and throughput at internet scale.

We build the infrastructure layer for agentic web interaction at scale. We are a small team with real scaling challenges, working with leading AI companies.

  • Drive Unreal Engine and UEFN development, writing clean code in C++, Verse, and Python.
  • Contribute to core systems improvements and build internal tools and pipelines.
  • Collaborate cross-functionally with engineers, designers, and producers in a supportive remote environment.

Disney Digital Entertainment redefines how audiences interact with The Walt Disney Company by creating a digital front door to unify its magic into an interactive universe. It is a division of Disney Entertainment with a remote team across the Nordic region focused on game engine technology.

$145,000–$160,000/yr
US Unlimited PTO

  • Design, develop, and maintain high-performance services for ExtraHop's core Framework systems.
  • Work across networking layers to implement and enhance protocol support, ensuring scalability and reliability.
  • Collaborate with cross-functional teams to translate business requirements into scalable engineering solutions.

ExtraHop is a cybersecurity company that provides network detection and response solutions. It has been operating since 2007 and serves organizations worldwide.

Canada

  • Lead complex cross-team technical initiatives to align architectural decisions and engineering approaches for the Android ecosystem.
  • Analyze technology stacks to identify performance bottlenecks and implement improvements across platform, runtime, and graphics subsystems.
  • Mentor engineers and contribute to strategic platform planning, including technical direction and long-term roadmap development.

Jobgether uses AI-powered matching to streamline job applications for candidates and employers. The company focuses on transparent hiring processes and offers opportunities in tech and other fields.

Canada

  • Define the technical direction of the web UI platform across performance, accessibility, consistency, and infrastructure.
  • Lead cross-team frontend initiatives, balancing long-term strategy with hands-on engineering and practical delivery.
  • Establish reusable patterns, standards, and tooling to improve developer velocity and product reliability.

Jobgether uses AI-powered matching to connect candidates with roles. It operates remotely with a focus on objectivity and fairness in hiring.

$150,000–$220,000/yr
US Canada

  • Develop high-performance C++ systems for real-time rendering and graphics pipelines.
  • Profile and optimize GPU/CPU performance across a wide range of devices, especially mobile.
  • Mentor team members and contribute to best practices in graphics and engine development.

thatgamecompany is a game development studio focused on creating high-quality social gaming experiences like Sky: Children of the Light. The company fosters a collaborative and inclusive culture, with a team of talented engineers, artists, and designers dedicated to pushing the boundaries of mobile and console gaming.

Global

  • Own the cost and performance of the inference stack, improving throughput and latency without compromising reliability.
  • Optimize through KV-cache management, continuous batching, speculative decoding, and quantization.
  • Work within serving engines like vLLM, SGLang, and TensorRT-LLM, profiling performance down to kernel level.

Adaption builds efficient AI that evolves in real-time, making intelligence flexible, personalized, and accessible to everyone. They focus on talent density, bringing together driven individuals to push the boundaries of continual adaptation.

US Unlimited PTO

  • Design, implement, and test distributed energy resource controls and telemetry software on customer hardware at sites around the world.
  • Develop high-performance, production-grade applications optimized for resource- and bandwidth-constrained environments.
  • Implement and enforce best security practices for critical infrastructure and cyber-physical systems, while mentoring junior engineers.

Verse is building an energy intelligence platform for the AI economy, helping large energy consumers achieve faster, cheaper, and cleaner power by combining real-time control of energy assets with complete visibility into their energy portfolio. The company is a high-growth startup backed by Bessemer, GV, Coatue, and NVIDIA, with a culture rooted in empathy, transparency, and thoughtful action.

Germany

  • Design and develop core networking components for a large-scale Virtual Private Cloud, including control-plane and data-plane systems.
  • Improve scalability, performance, and resilience of critical network services, implementing capabilities like IPv6, VPC peering, and load balancing.
  • Collaborate with engineering teams to deliver reliable, secure networking and participate in design reviews and coding interviews.

Our partner is a leading cloud infrastructure platform, enabling large-scale AI and cloud services. They foster a highly technical, international engineering environment with a trust-based culture and strong emphasis on ownership and continuous improvement.

$150,000–$200,000/yr
Global

  • Design, build, and maintain high-throughput, low-latency C++, Go, and Python services for core platform components.
  • Take complete ownership of the feature lifecycle from development through production deployment and ongoing operations.
  • Implement and integrate complex algorithms including tracking, inference, and sensor fusion into production services.

Cavnue, a Consor company, develops smart road technologies that deliver real-time digital twins of the roadway environment using AI, sensors, and cameras to improve safety and efficiency. We are building a diverse, remote-friendly team focused on engineering excellence and real-world impact.