Senior Software Engineer, Developer Tools
at Mozilla Corporation
Core Product-Firefox
Berlin Office

The Opportunity

Every modern web browser includes a powerful suite of developer tools built directly into the browser. These tools do a range of things, from inspecting currently-loaded HTML, CSS and JavaScript to showing which assets the page has requested and how long they took to load. We create and maintain the Firefox suite of developer tools, and our focus is on making inspection and debugging easy and efficient for web developers. We are passionate about Firefox and the web!  And we want all web developers to develop in Firefox.

Do you enjoy delighting people with solutions to their problems? Are you interested in learning how to write performant, secure code, and deliver it to hundreds of millions of people? If so, we’d love to hear from you.

What You'll Get To Do
  • Write code and tests, build prototypes, tackle problems with no clear solution, collaborate with other engineers to make developing in Firefox easier
  • Learn about a wide variety of problems and solutions across a large, mature code base
  • Develop a solid understanding of the strategy for your team, and contribute to it by suggesting ideas and recommending solutions to important issues
  • Help educate engineers on other teams through code reviews, giving talks, and/or writing documentation
  • Work with driven, committed team members to bring the open web to people around the world

What You Bring: Minimum Qualifications

  • 3+ years recent software development or programming experience
  • Excellent with JavaScript
  • Proficient with HTML, and CSS
  • Largely self-directed, able to resolve problems and mitigate risks independently
  • Can parallelize tasks to remain productive in a highly distributed, asynchronous environment.
  • Eager to learn, open to new ideas and challenging the old ways.
  • Go-to person for code reviews and/or discussions about your area
  • Write high-quality code and documentation
  • Communicate in a clear and concise manner

Bonus points for

  • Familiar with WebAPIs
  • Familiar with C/C++
  • Experience with Rust
  • Experience with Python
  • Experience with React/Redux libraries.
  • Experience working with distributed teams.
  • Experience working as a web developer

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


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