Senior Software Engineer – Localization & Internationalization (Python/JavaScript) | Mozilla
Mozilla is dedicated to keeping the internet open, accessible, and beneficial for everyone. We believe the web should remain a public resource — not controlled or restricted. By joining Mozilla, you contribute to shaping a more inclusive, innovative, and opportunity-driven online world.
About the Team & Role
The Localization Team builds and maintains the infrastructure that powers translation and localization across Mozilla’s products and services. The team also supports a global community of volunteer localizers who help bring Mozilla products to users worldwide.
As a Senior Software Engineer (Localization), you will contribute to core localization tools and technologies, including Pontoon (Mozilla’s Django-based Translation Management System) and open-source libraries such as moz-l10n. You will also help advance internationalization standards like Unicode MessageFormat and improve how Firefox and other Mozilla products adapt across languages and cultures.
This role involves technical leadership, architectural collaboration, and hands-on development across front-end and back-end systems.
What You’ll Do
-
Develop and maintain Python and JavaScript libraries supporting localization infrastructure
-
Design and implement new features within Pontoon (front-end and back-end)
-
Enhance internationalization (i18n) capabilities within Firefox and related products
-
Contribute to standards discussions around localization and internationalization
-
Collaborate with global volunteer contributors and internal teams
-
Participate in architectural planning and deliver high-quality, scalable software
What You’ll Bring
-
Strong experience building web applications using Python and JavaScript
-
Solid knowledge of APIs, web technologies, and modern development workflows
-
Experience with localization (l10n) and internationalization (i18n) concepts
-
Ability to work effectively in a distributed, cross-time-zone environment
-
Clear and thoughtful communication skills
-
Alignment with Mozilla’s core values of inclusivity, collaboration, accountability, and resilience
Also Read: Senior Full Stack Developer / CTO
Bonus Qualifications
-
Multilingual proficiency and understanding of linguistic nuances
-
Experience contributing to open-source communities
-
Programming experience in Rust or C++
Benefits & Perks
-
Performance-based bonus programs
Also Read: Crypto Market Operations Trainee -
Comprehensive health coverage (medical, dental, vision)
-
Retirement contributions with immediate vesting
-
Quarterly company-wide wellness days
-
Paid holidays plus birthday leave
-
Home office stipend
-
Annual professional development budget
-
Quarterly well-being stipend
-
Generous parental leave
-
Additional benefits depending on location
Join Mozilla to help build a more inclusive web and shape the future of global digital experiences.
