Jobs at Mozilla

Investigate and modify browser engine subsystems through hands-on experimentation, prototyping, instrumentation, profiling, and performance analysis. Build capabilities supporting reliable programmatic web interaction while evaluating correctness, compatibility, and efficiency. The role requires deep browser internals expertise, strong C++ or Rust proficiency, systems debugging experience, and understanding of web platform behavior. Engineers will collaborate with technical leadership, use AI-assisted development tools, and document reproducible results, including unsuccessful experiments.

Owns Firefox Mobile marketing operations across ASO, lifecycle campaigns, product launches, localization, quality assurance, and growth initiatives. Coordinates cross-functional workstreams, manages operational readiness, consolidates campaign performance data, and develops scalable processes, automation, and AI-assisted workflows using tools such as Claude Code and Cowork.

Build and ship full-stack features, integrations, and enterprise customizations for an open-source AI product. Work directly with technical partners and customers to support deployments, diagnose complex application and infrastructure issues, and convert deployment feedback into reusable product capabilities. Maintain customer-specific solutions, create documentation and runbooks, and collaborate with product and engineering teams on roadmap decisions. The role requires strong judgment, communication, and experience with AI-enabled applications and enterprise deployment environments.

Own Firefox mobile product development, primarily for iOS and also Android. Improve browser usability, performance, downloads, activation, retention, and differentiated features through user research, analytics, testing, and iteration. Collaborate with engineering, design, data science, and technical program management teams to ship improvements, monitor app health, optimize app-store presence, support global markets, and address local user needs.

Lead architecture and technical direction for Thunderbird’s web Services products, including calendar and secure file storage offerings. Design scalable systems, write code, build prototypes, establish software patterns, and contribute across development, testing, monitoring, and maintenance. Solve ambiguous technical and product problems, develop analytics and infrastructure, mentor engineers, collaborate with distributed cross-functional and open-source teams, and help improve user and subscriber growth.

Build, deploy, operate, and improve backend services and cloud infrastructure supporting Mozilla products. Responsibilities include backend development, API and data contract design, production monitoring, incident response, on-call support, releases, security and privacy reviews, code reviews, and mentoring. The role requires end-to-end service ownership, collaboration with frontend and cloud teams, and maintaining reliable production systems using modern observability and DevOps practices.

Design, develop, and maintain Thunderbird's iOS app with a focus on performance, reliability, security, accessibility, and scalability. Own projects end-to-end, debug and test across unit/integration/automation, review code, reduce technical debt, document architecture, and collaborate with product, UX, and the open-source community.

Build and improve Firefox WebCompat internal dashboards, reporting tools, and broken-site screenshot capture pipelines. The role involves creating reliable data views for triage and metrics, automating screenshot workflows, collaborating with WebCompat and QA teams, and translating reporting needs into effective tooling. Familiarity with WebCompat workflows, Bugzilla, screenshot automation, and machine learning is preferred.

Implement and ship approved UX improvements for Firefox screen, window, and tab sharing. Build accessible, tested, and localizable browser UI in a large codebase; collaborate with UX and QA, support testing with web conferencing services, and contribute through public code review. The role requires production front-end experience with JavaScript, HTML, and CSS, automated UI testing, rapid onboarding to mature codebases, and effective asynchronous communication.

Maintain and improve Firefox Graphics code covering rendering, compositing, images, canvas, and WebGL. Diagnose and fix cross-platform graphics issues, resolve bugs and regressions, maintain tests, review code, and manage incoming issues. The role requires strong C++ or Rust skills, graphics framework and GPU architecture knowledge, multithreaded debugging and optimization ability, and independent technical leadership in a mature codebase.

Maintains and improves Firefox’s Layout code across CSS, page layout, APZ, text, and images. Responsibilities include fixing bugs and regressions, keeping tests green, diagnosing cross-platform issues, conducting code reviews, handling routine upkeep, and participating in planning and web-compatibility meetings. The role requires independent technical leadership in a large, mature, multithreaded C++ codebase.

Lead full‑stack development and reliability improvements for the Firefox Add‑ons ecosystem, building features, automated moderation pipelines, reviewer tools, and observability. Improve platform reliability, respond to incidents, and help keep the ecosystem safe and trustworthy. Collaborate across design, product, QA, and community contributors and contribute openly through PRs and code reviews.

Leads the architecture, reliability, scaling, and evolution of hybrid-cloud and workplace infrastructure. Designs and operates production systems across data centers, offices, and cloud environments; drives migrations, automation, monitoring, incident response, and infrastructure improvements. Collaborates across IT, SRE, security, and service-owner teams, provides technical direction, mentors engineers, documents systems, and remains hands-on with critical implementations.

Build, maintain, and evolve Mozilla’s Internal Developer Infrastructure Platform: CI/CD, observability, Kubernetes optimization, environment bootstrapping, and cost optimization. Lead technical decisions, create Claude skills and agentic workflows to boost developer productivity, mentor teammates, write proposals, and deliver cross-functional platform features while ensuring usability, maintainability, and safe production paths.

Manage a portfolio of major donors, personally solicit and close five-, six-, and seven-figure gifts, and advance relationships through cultivation, solicitation, and stewardship. Maintain accurate Salesforce records, identify and qualify prospects, develop tailored proposals and impact stories, deliver stewardship activities, and partner with executives, program staff, and prospect research. The role also supports donor renewal, increased giving, annual-to-major gift pathways, and consistent revenue growth.

Lead Mozilla’s Marketing Data Science strategy and roadmap for Firefox. Drive attribution, ROI, campaign measurement, budget optimization, causal lift testing, brand impact analysis, retention and LTV modeling, audience segmentation, reporting infrastructure, dashboards, and scalable data tools. Mentor and develop team members, partner with cross-functional data science and marketing leaders, translate complex analyses into actionable recommendations, and evaluate emerging AI tools to improve workflows and business impact.

Define and execute Firefox Desktop search strategy across Windows, macOS, and Linux. Own search roadmaps, experimentation, engagement and revenue metrics, AI-powered search experiences, partner commitments, and cross-functional delivery. Balance user experience, privacy, technical constraints, and business outcomes while collaborating with Engineering, Design, Research, Data Science, and Business Development.