Staff Software Engineer - AMOMozilla

Remote UK 05-05-2023
Open Source
Hiring Ranges:
£81,000.00 GBP - £118,000.00 GBP

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The Role

Join the team at Mozilla responsible for building and maintaining the most powerful browser extensibility development ecosystem that empowers Firefox users to customize their browsing experience safely. Shape the future of web extensions by contributing to the design of the user journey from searching, selecting, and installing a web extension. Influence the operational support and the ecosystem's security by implementing innovative automated solutions.

Our ecosystem needs to handle information at a massive scale and extend well beyond searching a web extension. We're looking for engineers who bring fresh ideas from all areas, including information retrieval, distributed computing, large-scale system design, networking and data storage, security, artificial intelligence, natural language processing, UI design, and mobile; the list continues growing every day.

Join a distributed team of talented and diverse engineers working to maintain, secure and grow the Firefox add-ons ecosystem!

What is a Staff Software Engineer at Mozilla?

A Staff Software Engineer is the next level from a Senior Software Engineer. At Mozilla this role can vary but typically a Staff Engineer is a domain expert who leads others within a single team to tackle multi-month projects. Tasks that may be initially ambiguous or require significant planning and require them to influence or direct the work of several engineers. They sequence deliverables and manage risks in their team's projects, provide feedback on our strategy and goals affecting the team, and turn our strategy into action for their team members. Staff Software Engineers mentor others by stewarding some responsibilities to more junior and senior engineers so they can take on new ones. They collaborate with management on building team consensus and providing direction. Staff Software Engineers identify gaps and opportunities for improvement to enable a culture of inclusion and allyship, at all levels of the organization.


  • The Staff Software Engineer, Full Stack is responsible for planning, architecting, and delivering major frontend and full stack software components within (“AMO”)
  • Write and test product or system development code
  • Lead design reviews with peers and stakeholders to decide amongst available technologies
  • Review code developed by other developers and provide feedback to ensure best practices (e.g., style guidelines, checking code in, accuracy, testability, and efficiency)
  • Contribute to existing documentation and adapt content based on product/program updates and user feedback
  • Triage product or system issues and debug/track/resolve by analyzing the sources of issues and the impact on hardware, network, or service operations and quality
  • Collaborate with Mozillians across Product, UX, Design, Engineering, QA, Localization, Ops, and Legal to build, maintain, and expand core features
  • Write unit tests, automated regression tests, and track defects as they occur. Build performant, decoupled, testable, and maintainable code

What You Bring

  • 7+ years of software engineering experience and a Bachelor's degree in Computer Science, Mathematics or Engineering or its equivalent work experience 
  • 4+ years of experience using JavaScript, React/Redux
  • Experience with software development in one or more programming languages, and with data structures/algorithms
  • Experience testing, maintaining, and/or launching software products, and software design and architecture
  • Experience with front-end frameworks, full-stack development, and/or API development
  • Excellent communication skills. You can validate your decisions and communicate them clearly
  • Comfortable exploring solutions to complex problems and working collaboratively to pave the way forward in new problem spaces
  • The ability to mentor and inspire senior and junior developers

Bonus points for:

We value a variety of voices. You don’t need to check every box on this list to apply.

  • Python/Django experience
  • Experience collaborating with geographically distributed team members
  • Previous experience working in open source
  • Experience with security in front-end and back-end tech stacks
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, 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 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.

Group: D


Req ID: R2158


Applications are now closed