Senior Software Engineer (Localization) - Mozilla

The Localization Team manages the infrastructure that powers localization across all Mozilla products and services, and supports our global community of volunteer localizers. As a Senior Engineer, you’ll contribute to a range of Mozilla localization projects and technologies — from open source libraries like moz-l10n to Pontoon, our Django-based Translation Management System. You’ll also work on internationalization features that shape the experience of Firefox and other Mozilla products, and have the opportunity to engage with development of standards such as Unicode MessageFormat and DOM Localization. You’ll contribute to architectural discussions and help drive feature development within the team. At Mozilla, Senior Engineers are expected to work independently on well-defined projects, collaborate closely with peers, and play a key role in delivering high-quality software that advances the team’s goals and Mozilla’s mission. What you’ll do: Contribute to the development of Python and JavaScript libraries (such as moz-l10n) and tools that support Mozilla’s localization infrastructure. Improve localization and internationalization within the Firefox codebase to make features more adaptable and accessible across languages and regions. Collaborate with engineers and program managers to design and implement new Pontoon features. Engage with our community of volunteer developers and localizers to support and guide Mozilla’s localization efforts. Collaborate effectively with teammates and internal clients across regions and time zones. What you’ll bring: Strong experience developing and maintaining libraries and tools using Python and JavaScript. Solid understanding of web technologies, APIs, and modern development workflows. Experience with open source development practices and community collaboration. Ability to collaborate effectively in a distributed team, across time zones and disciplines. Excellent communication skills, with an emphasis on clarity and working across technical and non-technical roles. Professional fluency in English (written and verbal). Commitment to our values: Welcoming differences Being relationship-minded Practicing responsible participation Having grit Bonus points: Experience with internationalization (i18n) and localization (l10n) concepts, tools, or workflows. Programming experience in Rust and C++. Fluency in another language and understanding of linguistic diversity (e.g., grammar, plurals, text direction, and cultural conventions). What you’ll get: Generous performance-based bonus plans to all eligible employees - we share in our success as one team Rich medical, dental, and vision coverage Generous retirement contributions with 100% immediate vesting (regardless of whether you contribute) Quarterly all-company wellness days where everyone takes a pause together Country specific holidays plus a day off for your birthday One-time home office stipend Annual professional development budget Quarterly well-being stipend Considerable paid parental leave Employee referral bonus program Other benefits (life/AD&D, disability, EAP, etc. - varies by country) 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 hiringaccommodation@mozilla.com 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.