Staff Engineer, Front End (Desktop)

MZLA Technologies Corporation (MZLA) is a wholly owned, for-profit subsidiary of the Mozilla Foundation and home to Thunderbird, our flagship open-source email and productivity platform empowering more than 20 million people around the world. While part of the Mozilla portfolio of companies, MZLA operates independently in both identity and organizational structure from the Mozilla Foundation and Mozilla Corporation.

Everything we build at MZLA is open source, developed transparently and in collaboration with a global community of contributors. This open approach shapes not only our products but also how we work: collaboratively, inclusively, and with a shared commitment to building technology that puts users first. We believe privacy and productivity should coexist, and that people deserve powerful digital tools without surrendering control of their data.

MZLA is a small but growing team of 50+ people distributed across seven countries. As we evolve Thunderbird from a single application into a suite of privacy-respecting productivity tools, we’re introducing new products and services that remain independent of big tech ecosystems. Our unique revenue model combines community donations that keep Thunderbird freely available with subscriptions for new cloud-based services, allowing us to grow and innovate while remaining independent and true to our values.


The Opportunity:

As a Staff Software Engineer, Front-End, you’ll serve as a domain expert who deeply understands the complexities of shaping seamless, user-focused interfaces and delivering high-quality front-end solutions that align with product strategy. You’ll join a team of talented front- and back-end engineers who bring deep expertise to the development and maintenance of our flagship desktop application, cherished by millions of users worldwide for over 20 years.

You’ll work closely with engineers and cross-functional partners to tackle ambiguous problems in user experience, performance optimization, and architectural design. The ideal candidate has a strong focus on front-end architecture, user experience, and performance, and demonstrates technical leadership, sound judgment, and a collaborative approach to problem solving.

You’ll play a vital part in translating strategy into action by influencing technical direction, mentoring engineers at multiple levels, and ensuring that technical decisions align with MZLA’s mission and the objectives of the Thunderbird Project, particularly in delivering exceptional user experiences.

This is a full-time, remote position working with colleagues across multiple regions and time zones.

What you’ll do:

  • Lead complex, ambiguous technical initiatives requiring cross-team and cross-organization coordination
  • Own and deliver projects spanning new features, code quality improvements, tooling, and process optimization
  • Partner with senior engineers and product managers to define and execute technical strategy, reduce technical debt, and improve long-term maintainability
  • Collaborate closely with UX Engineers to ensure accessibility and usability are built in from the start (WCAG, ARIA)
  • Establish and promote scalable front-end architecture through shared frameworks and guidelines
  • Write high-quality, testable, and maintainable code; contribute to code reviews, testing, regression triage, and patch integration
  • Mentor and support engineers across the team, fostering a culture of learning and continuous improvement

What you’ll bring:

  • 10+ years of experience in front-end software development, building scalable, maintainable, and user-focused systems.
  • Extensive knowledge of modern vanilla JavaScript concepts (module patterns, async and promises, custom elements and shadow DOM), and up to date knowledge with the most recent ECMAScript specification.
  • Strong command of modern JavaScript frameworks such as React, Vue, or similar, and experience transitioning legacy codebases to new technologies.
  • Deep knowledge of HTML5 structures and advanced accessibility patterns and Deep knowledge of modern CSS patterns and methods.
  • In-depth understanding of system architecture, design patterns, and software engineering best practices, with a focus on performance, scalability, and maintainability.
  • Proven ability to act as a technical lead and mentor, providing guidance on complex technical problems and supporting the growth of other engineers.
  • Experience developing and testing applications across multiple platforms (Windows, macOS, and Linux), with expertise in Git or Mercurial and modern version control workflows.
  • Excellent communication and documentation skills, a collaborative approach to cross-functional work,
  • A strong commitment to continuous learning and improvement.

Bonus points for:

  • Experience contributing to or leading open-source projects
  • Experience with Python or other programming languages
  • Ability to engage with and support a global community of developers, including managing feedback and fostering an inclusive and productive ecosystem
  • Proficiency in French, German, Japanese, or another language in addition to English

Work Environment:

You’ll work with our passionate staff and open-source community members from all over the globe to support the mission and objectives of MZLA Technologies Corporation.

This is a remote position. Strong communication and documentation skills are essential for effective collaboration across time zones and disciplines.

What you’ll get:

We benchmark our base salaries to local markets and target the 60th percentile of the peer market. The salary ranges for this role are:

  • US: $150,000 - $175,000 USD

We may consider candidates with strong skills but less than the required experience. Title, level and compensation will be determined based on qualifications and experience.

In addition to competitive salaries, we offer a comprehensive benefits package designed to support your whole self, outlined below.

Work & Career

  • Fully remote work & schedule flexibility
  • Latest Laptop
  • Discretionary Annual Bonus Program
  • Monthly Remote Work Stipend
  • Annual Professional Development Stipend
  • Access to Udemy Learning Platform
  • Industry Conferences
  • Company All Hands

Rest & Play

  • 24 days PTO per year (prorated)
  • Your Birthday
  • Year-end Company Shutdown
  • 9 Wellbeing Days
  • Public Holidays
  • Other Paid Leave
  • Quarterly Wellbeing Stipend for Personal / Family Activities

Health & Family

  • 401(k) Contributions
  • Health, Dental, & Vision Insurance
  • Disability Insurance
  • Life Insurance
  • Employee Assistance Program
  • Paid Parental Leave
  • Paid Sick Days

Work Eligibility:

Applicants must reside in and have permanent work authorization for the country location(s) specified in the posting. We are unable to consider applicants outside of these markets at this time. And, we do not provide visa sponsorship.

How to Apply:

Please apply directly through our career page. We carefully review every cover letter and screening question, so take the time to answer each fully. We also value authenticity. We want to hear your perspective, not a bot’s. It's fine to use AI to polish your writing, but not to write your answers. Candidates who submit unoriginal AI generated answers will be disqualified from further screening.

MZLA Technologies Corporation (MZLA) Commitment to diversity, equity and inclusion

MZLA believes in the value of diverse creative practices and forms of knowledge, and knows diversity, equity and inclusion 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 not limited to) women, racialized and Indigenous persons, persons with disabilities, persons of all sexual orientations, gender identities and expressions.

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.

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 hiringaccomodations@thunderbird.net to request accommodation.

Back to blog

Common Interview Questions And Answers

1. HOW DO YOU PLAN YOUR DAY?

This is what this question poses: When do you focus and start working seriously? What are the hours you work optimally? Are you a night owl? A morning bird? Remote teams can be made up of people working on different shifts and around the world, so you won't necessarily be stuck in the 9-5 schedule if it's not for you...

2. HOW DO YOU USE THE DIFFERENT COMMUNICATION TOOLS IN DIFFERENT SITUATIONS?

When you're working on a remote team, there's no way to chat in the hallway between meetings or catch up on the latest project during an office carpool. Therefore, virtual communication will be absolutely essential to get your work done...

3. WHAT IS "WORKING REMOTE" REALLY FOR YOU?

Many people want to work remotely because of the flexibility it allows. You can work anywhere and at any time of the day...

4. WHAT DO YOU NEED IN YOUR PHYSICAL WORKSPACE TO SUCCEED IN YOUR WORK?

With this question, companies are looking to see what equipment they may need to provide you with and to verify how aware you are of what remote working could mean for you physically and logistically...

5. HOW DO YOU PROCESS INFORMATION?

Several years ago, I was working in a team to plan a big event. My supervisor made us all work as a team before the big day. One of our activities has been to find out how each of us processes information...

6. HOW DO YOU MANAGE THE CALENDAR AND THE PROGRAM? WHICH APPLICATIONS / SYSTEM DO YOU USE?

Or you may receive even more specific questions, such as: What's on your calendar? Do you plan blocks of time to do certain types of work? Do you have an open calendar that everyone can see?...

7. HOW DO YOU ORGANIZE FILES, LINKS, AND TABS ON YOUR COMPUTER?

Just like your schedule, how you track files and other information is very important. After all, everything is digital!...

8. HOW TO PRIORITIZE WORK?

The day I watched Marie Forleo's film separating the important from the urgent, my life changed. Not all remote jobs start fast, but most of them are...

9. HOW DO YOU PREPARE FOR A MEETING AND PREPARE A MEETING? WHAT DO YOU SEE HAPPENING DURING THE MEETING?

Just as communication is essential when working remotely, so is organization. Because you won't have those opportunities in the elevator or a casual conversation in the lunchroom, you should take advantage of the little time you have in a video or phone conference...

10. HOW DO YOU USE TECHNOLOGY ON A DAILY BASIS, IN YOUR WORK AND FOR YOUR PLEASURE?

This is a great question because it shows your comfort level with technology, which is very important for a remote worker because you will be working with technology over time...