Work on the Firefox DOM Core team to increase Session History test coverage and Gecko correctness by writing Web Platform Tests and mochitests, diagnosing and fixing issues in C++/JavaScript code, and iterating through public code review with Gecko module owners. Required: substantial browser-engine experience (ideally Firefox/Gecko), strong C++ and JavaScript skills, automated testing and debugging experience; preferred: prior Gecko or major browser-engine contributions and familiarity with web standards.

Maintain and engineer Firefox’s Graphics area: fix bugs and regressions, upkeep tests, diagnose and fix graphics problems across Windows/macOS/Linux/Android, and perform code review and routine maintenance so senior engineers can focus on performance. Requires strong C++ and/or Rust, knowledge of graphics frameworks and GPU architecture, and experience debugging and optimizing multithreaded codebases.

Work independently at a tech-lead level to keep Firefox Layout code healthy: fix bugs and regressions, keep tests green, diagnose and fix layout issues across Windows, macOS, Linux and Android, perform code review, and participate in planning and web-compat/standards meetings. Strong C++, CSS and multithreaded debugging/optimization skills required; JavaScript/Rust and browser/web-standards experience are a plus.

Work on feature development and architectural improvements across the Add-ons stack (DevHub, Reviewer tools, automated moderation). Build and operate production services with emphasis on reliability, CI/CD, observability, and developer platform tooling. Collaborate with engineers, reviewers, product, and community contributors; write design docs, ADRs, runbooks, and contribute in the open.

Work on AMO to deliver features and architectural improvements across submission flows, automated moderation pipelines, DevHub and Reviewer tools. The role involves Python/Django backend work, React/TypeScript frontend, MySQL, asynchronous processing, improving CI/CD and developer platforms, observability, incident response, and writing technical documentation (ADRs, runbooks).

Work on the addons.mozilla.org stack to deliver features and architectural improvements across DevHub, Reviewer tools and automated moderation pipelines. The role centers on Python/Django backend work, React/TypeScript front-end, CI/CD and platform reliability (observability, deployments, incident response), and contributing to internal developer platforms and engineering standards.

Join Mozilla's Add‑Ons team to deliver features and architectural improvements across AMO (DevHub, Reviewer tools, automated moderation). Role emphasizes Python/Django backend development, CI/CD and pipeline-as-code, observability (metrics, logging, tracing, SLOs), platform reliability, internal developer tooling, and production incident practices. Position is remote (UK) with a listed salary range of £66,000–£87,000.

Work on AMO systems including DevHub, Reviewer tools, automated moderation pipelines, and internal developer platforms. The role emphasizes Python/Django backend work, React/TypeScript frontend, CI/CD and infrastructure-as-code, observability and SRE practices, technical documentation, and contributing in the open.

Remote (Spain) Senior Software Engineer role on the Add-ons team to deliver features and architectural improvements across AMO (DevHub, Reviewer tools, moderation pipelines). Work includes backend and frontend development (Python/Django, React/TypeScript), improving CI/CD and infrastructure-as-code, building observability and reliability practices, and contributing in the open. Salary range listed: €58,000–€77,000 EUR (annual).

Join Mozilla’s Add-ons team to deliver features and architectural improvements across AMO (DevHub, Reviewer tools, automated moderation). Role centers on Python/Django backend, React/TypeScript frontend, CI/CD and infrastructure-as-code, observability, reliability and incident response. Hiring range for Remote Belgium: €56,000–€74,000 EUR/year.

Join the Add‑Ons team to deliver features and architectural improvements across AMO, DevHub, Reviewer tools, and automated moderation systems. The role involves Python/Django backend and React/TypeScript frontend work, improving CI/CD and observability, operating production services, and contributing in the open. Remote role based in Sweden; listed salary range: 512,925–683,900 SEK per year.

Remote staff full-stack product engineer role at Thunderbird/Thunderbolt focused on building full-stack features, integrations, and customer-specific customizations for enterprise AI deployments. Requires 10+ years of software engineering experience, strong TypeScript/JavaScript and backend/API skills, experience with AI-enabled applications (LLMs, RAG, agents), and familiarity with enterprise deployment concerns (authentication, identity, self-hosted/hybrid infrastructure, observability). Role includes hands-on coding, supporting partner- and customer-hosted pilots and productions, and writing documentation and runbooks.

Full-time, fully remote Senior Software Engineer (iOS) role focused on designing, developing, and improving Thunderbird’s iOS application. Responsibilities include building mobile architecture, improving performance and reliability, testing, debugging, code review, security and accessibility work, and collaborating with product, UX, and open-source contributors. Position is targeted to residents of Canada, offers a CAD salary range of 108,000–125,000, and does not provide visa sponsorship.

Full-time, fully remote (US) Senior Software Engineer, iOS role at MZLA/Thunderbird to contribute to and improve the iOS application’s architecture, performance, reliability, security, and accessibility. Requires 7+ years professional software development (including 2+ years at senior level), strong Swift/SwiftUI skills, mobile app development and security experience, and familiarity with email/communication protocols.

Full-time remote Senior Software Engineer (iOS) to contribute deep iOS expertise to Thunderbird’s mobile product: build and refine architecture, improve performance, reliability, security, and maintainability, collaborate with product/UX and the open-source community. Requires 7+ years professional software development (including 2+ years senior), 3+ years mobile experience, strong Swift/SwiftUI skills, and experience with testing, debugging, Git, and mobile security.

Work on Firefox's Platform Layout/APZ team to design and implement standards-compliant layout, rendering, and Asynchronous Pan & Zoom features across platforms. Requires experience with C/C++ and/or Rust, multi-threaded debugging, memory and performance optimization, and contributing to or working with large open-source codebases.

Work on standards-compliant layout, CSS, rendering and APZ (Asynchronous Pan & Zoom) in Gecko for Firefox across Android, Windows, Linux and macOS. Responsibilities include writing high-quality performant C/C++ or Rust code, debugging and optimizing multi-threaded systems, participating in code reviews, triaging bugs, and contributing to open-source browser development. Requires strong debugging and performance skills, experience with memory and performance tools, and the ability to work with a large codebase.

Work on Gecko’s layout and APZ (Asynchronous Pan & Zoom) to develop standards-compliant CSS and page layout features across Android, Windows, Linux, and macOS. Requires C/C++ and/or Rust development, strong multi-threaded debugging and performance/memory optimization skills, and experience contributing to or working with open source/browser projects.

Responsible for maturing, maintaining, and building features for Mozilla's Internal Developer Infrastructure Platform, including CI/CD, observability, Kubernetes optimization, environment bootstrapping, and cost optimization. Requires 5+ years software engineering experience, technical leadership, proficiency in Python/JavaScript/Go, and strong experience with cloud-native technologies (GCP preferred, AWS acceptable) and tools such as ArgoCD, Grafana, Terraform, Helm, Backstage.

Work on full-stack features and architecture for addons.mozilla.org (DevHub, Reviewer tools, automated moderation pipelines). Responsibilities include React/TypeScript frontends, Django backend, MySQL, observability, deployments, monitoring, incident response, security, and collaborating with engineers, reviewers, product, and community contributors. Role emphasizes open-source collaboration and ecosystem safety.