Senior Security Engineer, -ons Operations

About This Team And Role

addons.mozilla.org (AMO) is the foundation of the Firefox add-ons ecosystem. It showcases developers to publish and grow their extensions, and serves as a discovery platform for millions of users who customize Firefox. Behind the scenes are the Dev Hub which enables developers to manage their extensions. To manage the ecosystem there are a series of Reviewer tools and automated moderation systems.

• Deliver major features and architectural improvements across the Add-ons stack, including automated moderation pipelines, Reviewer tools, and Dev Hub.
• Create robust observability systems and data‑backed insights.
• Provide peer feedback, share knowledge and help others grow.
• Improve platform reliability through deployments, monitoring, and incident response.
• Help keep the platform safe and trustworthy, with attention to security and user trust.
• Step in to resolve issues impacting users and developers, from small bugs to larger incidents.
• Collaborate with designers, product managers, QA, and community contributors to deliver end‑to‑end improvements.
• Contribute in the open through pull requests, code reviews, and discussions.
• Work on:
  • Full‑stack development:
    React/Type Script frontends, Django backend, MySQL datastore.
  • Platform reliability: deployments, monitoring, and incident response on Google Cloud.
  • Feature development: submission flows, trust and safety signals, Dev Hub and Reviewer tools modernization.
  • Ecosystem moderation: abuse report management, policy compliance, and ecosystem safety.
  • Open collaboration:
    We work in the open, with contributions from Mozilla staff and community members.

• Experience building modern web applications.
• Strong experience with Python/Django or similar backend frameworks.
• Understanding of web security principles and practices.
• Strong collaboration and communication skills in a distributed team environment.
• Adept at navigating ambiguity, exploring solutions, and shaping direction in new problem spaces.
• Commitment to our values:
  • Welcoming differences
  • Being relationship‑minded
  • Practicing responsible participation
  • Having grit

• Experience in building automated security systems.
• Exposure to cloud infrastructure (Google Cloud or similar).
• Contributions to open source projects.
• Experience with policy‑compliant ecosystem moderation tools.

• Generous performance‑based bonus plans to all eligible employees – we share in our success as one team
• Rich medical, dental, and vision coverage
• Generous retirement contributions with 100% immediate vesting (regardless of whether you contribute)
• Quarterly all‑company wellness days where everyone takes a pause together
• Country specific holidays plus a day off for your birthday
• One‑time home office stipend
• Annual professional development budget
• Quarterly well‑being stipend
• Considerable paid parental leave
• Employee referral bonus program
• Other benefits (life/AD&DD, disability, EAP, etc. – varies by country)

Mozilla understands that valuing diverse creative practices and forms of knowledge are crucial to and enrich the company’s core mission. We encourage applications from everyone, including members of all equity‑seeking communities, such as (but certainly not limited to) women, racialized and Indigenous persons, persons with disabilities, persons of all sexual orientations, gender identities, and expressions.

We will ensure that qualified individuals with disabilities are provided reasonable accommodations to participate in the job application or interview process, to perform essential job functions, and to receive other benefits and privileges of employment, as appropriate. Please contact us at hi to request accommodation.

We are an equal opportunity employer. We do not discriminate on the basis of race (including hairstyle and texture), religion (including religious grooming and dress practices), gender, gender identity, gender expression, color, national origin, pregnancy, ancestry, domestic partner status, disability, sexual orientation, age, genetic predisposition, medical condition, marital status, citizenship status, military or veteran status, or any other basis covered by applicable laws.

Mozilla will not tolerate discrimination or harassment based on any of these characteristics or any other unlawful behavior, conduct, or purpose.

Canada Tier 1 Locations: $104,000—$139,000 CAD

Canada Tier 2 Locations: $94,000—$126,000 CAD