Add-ons Code Security Reviewer
at Mozilla Corporation
Core Product-Firefox
Remote Germany, Remote US, Remote Canada, Berlin Office

The Company

Our unique corporate structure guarantees that every decision we make upholds our mission: to make sure the internet stays available, safe, and welcoming to everyone. Beholden to neither shareholders nor investors, Mozilla Corporation is wholly owned by the not-for-profit Mozilla Foundation.

Along with 20,000+ volunteer contributors and collaborators all over the world, Mozilla Corporation’s staff designs, builds, and distributes software that allows people to enjoy the internet on their own terms. Our flagship product — the Firefox browser — has expanded into a family of products that protects users and alerts them of risks.

The Role

Add-ons (or “browser extensions”) are software programs, most often developed by a third party, that allow you to add features to Firefox to customize your browsing experience. With billions of downloads and millions of users every day, add-ons are a significant part of the Firefox experience.

Mozilla is looking for a Code Security Reviewer to join the Firefox Add-ons team, to keep users safe from malicious extensions and support developers with add-on development.

You will be engaging in special projects to increase the effectiveness of our review pipeline, monitoring existing signals and create new rules to detect add-ons of interest, and take action against malicious activity on

As a code security reviewer, you will:

  • Review add-ons for security, functionality, user experience, and compliance with submission guidelines and add-ons policies.
  • Resolve complicated operational issues, or also compliance issues raised by other reviewers.
  • Assist add-on developers in resolving questions, compliance, conflicts, and other review issues.
  • Identify areas of improvement in review tools and operations, and collaborate with the add-ons engineering team to optimize them.
  • Work on add-ons ecosystem related projects, using development, documentation, and other technical skills.

Your Professional Profile

  • 3+ years of professional experience and proficiency in JavaScript, including more recent additions to the specification (ES6+), and a proven grasp of the web platform (JS, HTML, CSS, DOM).
  • A background in creating or reviewing browser extensions.
  • Experience reviewing code from a client security perspective.
  • Strong analytical skills and decision making, to support effectively identifying malicious add-ons and inferring behavior from complex, obfuscated or minified code.
  • Ability to work with command line and build tools commonly used in JavaScript environments.
  • Experience collaborating remotely and asynchronously with an international team.
  • Excellent written and verbal communication skills in English.

Things that might set you apart from other applicants:

  • Empathy for the experience of our community of users, developers, and volunteers, advocating for them based on community insights.
  • Experience with one or more of Python, Django and React.
  • Ability to create SQL queries to support metrics and analysis.

Does this sound like the right challenge for your next endeavor? We'd love to hear from you and make you a part of our team!.

About Mozilla 

Mozilla exists to build the Internet as a public resource accessible to all because we believe that open and free is better than closed and controlled. When you work at Mozilla, you give yourself a chance to make a difference in the lives of Web users everywhere. And you give us a chance to make a difference in your life every single day. Join us to work on the Web as the platform and help create more opportunity and innovation for everyone online.

Commitment to diversity, equity, inclusion, and belonging

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, radicalized 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 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.



Why Mozilla?

At Mozilla, we’re serving humanity—by maintaining a safe, open internet—while also helping the individual humans employed here to reach their personal and professional goals. With a relatively small team serving hundreds of millions of people, a culture of exploration, and a commitment to mentorship, opportunities abound to learn and grow at Mozilla.

Our values drive our actions

  • Purpose is built into our work, with our mission driving every decision
  • We challenge assumptions, the status quo, ourselves, and each other
  • We are transparent: in our code, our business partnerships, and our everyday interactions
  • We seek out people from diverse backgrounds and with perspectives different from our own
  • We pair purpose with performance and put people ahead of profit

Our impact is global

  • 700+ paid staff from over 30 countries
  • Thousands of volunteer contributors across six continents
  • 9 global offices: Mountain View, San Francisco, Portland, Vancouver, Toronto, Paris, London, Berlin, and Beijing
  • Hundreds of home offices globally

Our benefits are world-class

  • Flexible work environment (nearly half of Mozillians work remotely)
  • Industry-leading paid parental leave (up to 26 weeks of fully paid leave for childbearing parents and up to 12 weeks for non-childbearing parents)
  • Reimbursement for professional development (up to $3,000/year)
  • A work setup including the latest hardware and software of your choice