Release Engineer

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.

To learn more, visit www.thunderbird.net

The Opportunity:

As a Release Engineer you will play a key role in building, maintaining, and evolving the automation systems that power Thunderbird’s software releases across desktop and mobile platforms (Linux, Windows, macOS, Android, and iOS).

You’ll join the Release Operations team, which is responsible for ensuring our builds are reliable, reproducible, secure, and delivered on time to millions of users worldwide. This team operates at the intersection of engineering, infrastructure, and product delivery, strengthening our automation systems and enabling developers to ship with confidence.

Because Thunderbird shares upstream technologies with Firefox, you will collaborate across the broader Mozilla ecosystem to adapt and integrate build system changes into Thunderbird’s release pipeline.

What you’ll do:

• Develop and maintain workflows for automating software builds and releases, including managing dependencies and toolchains.

• Write and enhance CI / CD workflows, packaging, and installation scripts for Thunderbird on Linux, Windows, macOS, Android, and iOS platforms.

• Adapt changes to build scripts made by the Firefox engineering teams to Thunderbird.

• Identify, troubleshoot, and resolve complex build, test, and dependency issues in collaboration with developers and contributors.

• Participate in process improvement initiatives, contribute to the evaluation and design of alternative solutions, and support ad hoc projects as required.

• Ensure the timely and high-quality delivery of Thunderbird releases.

• Engage with the open-source community to gather feedback, address concerns, and foster collaboration.

What you’ll bring:

• 3+ years of professional experience, including build and release engineering for applications on Linux, Windows, macOS, Android, and iOS platforms.

• Proficiency in C, C++, Rust, Kotlin, and Java, including knowledge of related toolchains and dependencies.

• Strong understanding of Python and shell scripting for automation, version control, and CI/CD pipelines.

• Experience building, compiling, and release engineering native desktop or mobile applications, with demonstrated ability to debug complex build and compile issues.

• Working knowledge of containerization technologies such as Docker and Kubernetes, distributed version control systems (Mercurial and Git), and DevOps principles and cloud-based infrastructure such as AWS or GCP.

• Demonstrates strong ownership of assigned tasks, ensuring timely completion and proactively managing multiple simultaneous requests, working both independently and as part of a team.

• Excellent English written and verbal communication skills, with the ability to clearly and concisely engage with an international, geographically distributed team.

• Commitment to open-source development and open standards, with proven ability to independently complete projects on time and with high quality.

Bonus points for:

• Familiarity with JavaScript and CSS for front-end support and integration.

• Experience with Taskcluster or similar CI systems.

• Low-level system experience with Linux, Windows, and/or macOS.

• Familiarity with legacy build systems (e.g., Make) and modern systems (e.g., Bazel, Buck, Blaze).

• Previous experience contributing to open-source projects or engaging with open-source communities.

Work Environment:

You’ll work with passionate staff and open-source community members from all over the globe to support the mission and objectives of MZLA and Thunderbird. Strong communication and documentation skills are essential for effective collaboration.

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: $103,000 - $122,000 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 [email protected] to request accommodation.