Senior Software Engineer, Accessibility

Why Mozilla?

Mozilla Corporation is the non-profit-backed technology company that has shaped the internet for the better over the last 25 years. We make pioneering brands like Firefox, the privacy-minded web browser. Now, with more than 225 million people around the world using our products each month, we’re shaping the next 25 years of technology and helping to reclaim an internet built for people, not companies. Our work focuses on diverse areas including AI, social media, security and more. And we’re doing this while never losing our focus on our core mission – to make the internet better for people. 

The Mozilla Corporation is wholly owned by the non-profit 501(c) Mozilla Foundation. This means we aren’t beholden to any shareholders — only to our mission. Along with thousands of volunteer contributors and collaborators all over the world, Mozillians design, build and distribute open-source software that enables people to enjoy the internet on their terms. 

About this team and role:

At Mozilla, accessibility (or a11y for short) is an integral part of our mission to ensure the internet is "open and accessible to all," helping to empower people, regardless of their abilities, to contribute to the common good.

To that end, the Accessibility Team maintains the Firefox accessibility engine used by assistive technology software, as well as other accessibility specific features such as high contrast mode support. In addition, the team seeks to guide and educate design and product teams in crafting accessible Mozilla products or features. This supports Mozilla's ambition of creating a joyful internet for all.

The Mozilla Corporation is looking for a skilled developer to work with our passionate Accessibility Team to make the web fully accessible! This is a small, hard-working team that affects the lives of users every day. Using your C++ and systems programming expertise, you will contribute to the core Gecko web rendering engine across various operating systems, shaping Mozilla’s efforts to take Firefox accessibility to the next level.

Opportunities to collaborate with other browser teams abound, and working in the open is the norm. You’ll be responsible for writing code, tests, specifications, building prototypes, solving problems, and analyzing data. You'll get feedback from real users and synthesize it into bug reports, feature designs, and strategic direction to make the web platform even better over time.

• Improve the architecture, stability, correctness and performance of the core Gecko accessibility engine.


• Debug and fix problems in our multi-process, multi-threaded codebase.


• Debug OS specific issues.


• Build excellent working relationships with engineers and organizational leaders on other teams.


• Collaborate with design and front-end teams to identify, assess, and remediate accessibility issues.


• Influence web standards that provide or improve access to new web technology.


• Work in the open as part of the Mozilla open source project and engage with Mozilla’s global community.


• Work on infrastructure to expose the web platform to accessibility technology.


• Meet standards for gecko's memory usage and performance.


• Implement new web features to enable new kinds of applications and content types.

What you'll bring:

• A degree or equivalent in Computer Science or a related field.


• Demonstrated proficiency with C++.


• Knowledge of web accessibility and ARIA.


• Knowledge of Javascript, the web, and web applications.


• Experience working on cross-platform native applications.


• Creative problem-solving and debugging skills.


• Experience writing and debugging multi-process, multi-threaded code.


• Ability to learn a large and complex multi-language code base.


• Excellent written and verbal English communication skills.


• Ability to effectively participate as part of a geographically-distributed open development team.


• A passion to empower and improve the web for people with a diverse range of abilities.

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 orientation s, 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 View email address on jobs.jobcopilot.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.

Group: D

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Req ID: R3181

Hiring Ranges:

Canada Tier 1 Locations

$104,000 - $139,000 CAD

Canada Tier 2 Locations

$95,000 - $126,000 CAD