Software Engineer - Dev Tools Engineer

Team: Business Development

Locations: Berlin

Why join Mozilla engineering?

Learn: Code review at Mozilla includes pushing to passionate contributors around the world. Building Firefox and its family of products requires knowledge up and down the stack, and extremely high standards for security and optimization. Beyond the browser, we’re developing AR/VR, IoT, and voice recognition products that respect and protect privacy.

Grow: We’re dedicated to helping every team member develop. We give engineers trust and responsibility from day one, offer generous stipends for learning opportunities, and provide mentorship, especially around key leadership skills like collaboration and clear, kind communication.

Make Your Mark: We’re small but mighty, challenging the biggest behemoths on the internet with a staff the size of their marketing departments. That means every engineer can have an outsized impact on products that touch tens of millions of users—ultimately influencing how the entire internet works.

At Mozilla we want to make Firefox a delightful product for our users. We are engineers, designers, makers, and problem solvers. We work in the fishbowl known as the open source community, with a clear focus on making the Web better.

We are looking for technically curious people to be part of the team. This isn’t just a fantastic place to work; it’s an experience you’ll carry with you throughout your career.

The Role

We're looking for a JavaScript engineer who cares about shipping great tools and wants to make web developers happier and more productive.

You'll be mostly writing and reviewing code, but we also expect you to get involved in the team's planning process, provide technical insights and make decisions.

We have lots of interesting problems to solve, since ours is a UI heavy interface which has to display lots of information in a way that is useful and relevant to users, but also does not slow down the machine or alter the examined code.

Our code base is essentially written in JavaScript, HTML and CSS, and there are frequent opportunities to dive deeper into the Firefox side, write C/C++ (or perhaps even Rust), and learn new things.

In addition to fostering a very lively community of contributors to our project, we are also heavy users of open source components such as React, Prettier, ESlint and node.js.

Our team is distributed across various time zones, with roughly half of our people working from their home offices.

The Person

  • You're comfortable contributing with code.
  • You love helping your colleagues grow and get better at what they do.
  • You are happy to provide and receive constructive feedback; when you see a chance to improve something, you act on it.
  • You have experience participating in product and strategy planning, and can communicate effectively with other functions, such as product and project managers.
  • You are not afraid to ask questions, and propose new ideas if you think they will make a positive impact.
  • You are capable of working asynchronously on complex technical problems.
  • You have strong written and verbal English skills.


  • You write clear and maintainable code.
  • You do careful and thorough code reviews that improve the system and help everyone learn.
  • You break down complex problems into smaller parts, so that more work can be done in parallel.
  • You assess the right priorities of projects and tasks, identify valuable opportunities and determine what's most important right now.
  • When it comes to conflict, you build consensus on complex issues, through your empathy, internal credibility and visibility.
  • You find answers to questions, even if that means digging deep into legacy or third-party code. When you are done, the code is in an even better state than when you started.
  • You can switch context easily and work on several projects.
  • You are comfortable designing and implementing new APIs, as well as discussing technical design decisions with colleagues.
  • You know how to approach an existing codebase and improve its architecture through small, planned interventions.

You have working knowledge of

  • JavaScript
  • CSS
  • HTML
  • Version control systems, particularly Git or Mercurial (we use Mercurial)
  • Test driven development

Nice to know, but that can be learned on the job:

  • C++
  • Rust

Feel good about your work again.

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

  • 1000+ paid staff from over 30 countries
  • Thousands of volunteer contributors across six continents
  • 10 global offices: Beijing, Berlin, London, Paris, Mountain View, Portland, San Francisco, Taipei, Toronto and Vancouver
  • 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
  • Wellness programs—we reimburses up to $1700/year for expenses like child and elder care, mental wellness, and personal enrichment

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.

We are an equal opportunity employer and value diversity. We do not discriminate on the basis of race, religion, color, national origin, gender, sexual orientation, age, marital status, veteran status, or disability status.

A lot of companies say they’re “mission-driven.” 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. Mozilla’s Emerging Technologies group incubated and sponsors Rust — Stack Overflow’s “most loved programming language” for the last four years — and is building safe, private versions of virtual reality, internet of things, and voice recognition.

How to apply

Apply here.

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