# Senior Software Engineer — Firefox
## About the Role
Mozilla is seeking a Senior Software Engineer to join the Firefox team and help build high-quality, secure, performant, and accessible user interfaces for the Firefox browser. The team works on a large, mature, open-source codebase supporting Firefox across Windows, Linux, and macOS.
This is a geographically distributed role where engineers collaborate openly across teams and contribute to products used by hundreds of millions of people. The Senior Software Engineer will work on interface development, testing, performance, security, accessibility, maintainability, and engineering practices while helping other engineers succeed through collaboration, code reviews, documentation, and knowledge sharing.
## Key Responsibilities
Build high-quality user interfaces for Firefox with accessibility and usability in mind.
Write production code and tests.
Build prototypes and solve complex problems where solutions may not be clearly defined.
Collaborate with designers and engineers to develop and improve Firefox interfaces.
Work across a large and mature codebase to understand and solve a wide variety of technical problems.
Collaborate with cross-functional teams and build relationships to achieve shared goals.
Support the development of fellow engineers through code reviews, technical talks, and documentation.
Maintain high standards for code quality, with a focus on:
Performance
Testing
Security
Usability
Accessibility
Maintainability
Contribute to engineering practices and procedures.
Participate in a distributed team through effective written and verbal communication.
Contribute to Mozilla's open-source engineering environment.
## Required Qualifications
4+ years of experience as a software engineer.
Background in shipping high-quality software.
3+ years of professional experience with JavaScript, HTML, and CSS.
Ability and interest in working with a geographically distributed team.
Strong asynchronous written communication and verbal communication skills.
Willingness to provide and receive constructive feedback.
Ability to ask questions and propose new ideas.
Collaborative approach to working with others.
## Preferred Qualifications The source description does not specify additional technical preferred qualifications.
## Skills & Competencies
Software Engineering
JavaScript
HTML
CSS
User Interface Development
Web Development
Accessibility
Usability
Performance Optimization
Software Testing
Application Security
Code Quality
Maintainability
Prototyping
Code Review
Technical Documentation
Cross-Functional Collaboration
Distributed Team Collaboration
Open-Source Software
## Education & Experience
Education
No specific educational degree is stated in the source description.
Experience
4+ years of software engineering experience.
3+ years of professional experience with JavaScript, HTML, and CSS.
Experience shipping high-quality software.
## Work Arrangement & Schedule
Work Arrangement: Remote / geographically distributed team.
Team Environment: Distributed and collaborative, with asynchronous communication as an important part of the working model.
Platforms: Firefox development across Windows, Linux, and macOS.
Req ID: R3135
## Compensation & Benefits
Hiring Ranges
| Location Tier | Salary Range |
| ------------------- | --------------------: |
| US Tier 1 Locations | $137,000–$183,000 USD |
| US Tier 2 Locations | $126,000–$168,000 USD |
| US Tier 3 Locations | $116,000–$155,000 USD |
Benefits include
Performance-based bonus plans for eligible employees
Medical, dental, and vision coverage
Retirement contributions with 100% immediate vesting
Quarterly company-wide wellness days
Country-specific holidays and birthday time off
One-time home office stipend
Annual professional development budget
Quarterly well-being stipend
Paid parental leave
Employee referral bonus program
Other benefits such as life/AD&D, disability, and EAP, varying by country
## About Mozilla
Mozilla Corporation is a technology company wholly owned by the nonprofit Mozilla Foundation. Mozilla develops open-source software, including Firefox, with a focus on building an internet that is accessible to people.
The Firefox team develops and maintains the browser across desktop platforms and works with engineers, designers, and other teams to improve the security, performance, usability, and accessibility of the web experience.
## Diversity, Equity, Inclusion & Accessibility
Mozilla encourages applications from people with diverse backgrounds and perspectives. Qualified individuals with disabilities may request reasonable accommodations during the application and interview process and while performing essential job functions.
Mozilla is an equal opportunity employer and states that it does not discriminate based on characteristics protected by applicable laws.