At a Glance
- Tasks: Develop and maintain WebExtensions APIs, ensuring safety and performance for millions of users.
- Company: Join Mozilla, a leader in open-source technology with a commitment to innovation.
- Benefits: Enjoy competitive pay, health coverage, remote work options, and generous professional development support.
- Other info: Collaborative environment with a focus on diversity, equity, and inclusion.
- Why this job: Make a real impact on user experience while working with cutting-edge web technologies.
- Qualifications: 4+ years in software development, strong JavaScript skills, and experience with API design.
The predicted salary is between 50000 - 70000 £ per year.
About this team and role: The WebExtensions platform powers the add-ons ecosystem in Firefox, enabling millions of users to customize their browser while keeping safety and performance at the forefront. As a WebExtensions Engineer, you will help implement new extension capabilities, improve existing APIs, and ensure that extensions remain reliable across Firefox. As a Software Engineer on the WebExtensions team, you’ll bring a passion for exploring complex systems and creating experiences that balance developer power with user trust. You’ll work deep in the Gecko platform to evolve extension capabilities, and you’ll build UI features in Firefox that make extensions clear and manageable for users. Along the way, you’ll collaborate with experts across Mozilla and help advance cross-browser compatibility and the path toward standardization. Your work will keep extensions safe, powerful, and reliable for developers and millions of Firefox users.
What you’ll do:
- Implement and maintain WebExtensions APIs and Addon Management, balancing power, safety, and performance, as well as user interfaces in Firefox.
- Debug and fix issues affecting extensions in Firefox.
- Collaborate with product managers, QA, and the AMO engineering team to deliver features end-to-end.
- Contribute to Mozilla-owned extensions and system add-ons.
- Participate in open source workflows: code reviews, pull requests, and discussions in Bugzilla/GitHub.
- Support extension developers by helping diagnose issues and improving tooling/documentation.
What you’ll bring:
- 4+ years of professional experience in software development.
- Strong proficiency in JavaScript, DOM APIs, HTML, and CSS.
- Familiarity with modern browser architecture and debugging tools.
- Experience with API design and integration.
- Ability to navigate and learn from large codebases.
- Strong communication skills and experience collaborating in distributed teams.
Bonus points for:
- Experience with Firefox internals, C++ or Rust.
- Familiarity with Android or GeckoView development.
- Knowledge of web security principles.
- Contributions to open source projects, especially in browser or extension development.
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).
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.
Equal Opportunity Employer: 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.
Senior Software Engineer, WebExtensions Remote UK employer: Mozilla Corporation
Mozilla is an exceptional employer that champions innovation and collaboration within a diverse and inclusive work culture. As a Senior Software Engineer on the WebExtensions team, you will enjoy generous benefits including performance-based bonuses, comprehensive health coverage, and a commitment to professional development, all while working remotely in the UK. With a focus on employee well-being and a strong emphasis on open-source contributions, Mozilla provides a unique opportunity to make a meaningful impact on millions of users worldwide.
StudySmarter Expert Advice🤫
We think this is how you could land Senior Software Engineer, WebExtensions Remote UK
✨Join Local Tech Meetups
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✨Contribute to Open Source Projects
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We think you need these skills to ace Senior Software Engineer, WebExtensions Remote UK
Some tips for your application 🫡
Show off your coding skills:When applying for a software engineering role, it's super important to showcase your coding skills. Make sure your CV includes your tech stack, any relevant programming languages you’re comfortable with, and examples of projects you've worked on. If you have a GitHub profile, link it up! We love to see code in action.
Tailor your portfolio:For a full-time role, we’d expect to see some solid examples of your work in your portfolio. Make sure to include at least two or three projects that highlight your problem-solving skills and your ability to work with different technologies. Focus on the projects that are most relevant to the position at Mozilla Corporation.
Craft a killer cover letter:Your cover letter is your chance to stand out—make it personal! Explain why you want to work at Mozilla Corporation and how your skills align with the role. Show us your passion for software development. We dig enthusiastic candidates who understand the value of collaboration and continuous learning!
Be clear and concise:When it comes to writing your CV and cover letter, clarity is key. Avoid jargon that could confuse us and stick to simple, direct language. Highlight your achievements with quantifiable results where possible, and keep everything easy to read. A well-organised application goes a long way!
How to prepare for a job interview at Mozilla Corporation
✨Brush Up on Your Coding Skills
For a full-time software engineering role, it's crucial that we stay sharp with our coding abilities. Expect technical questions that might involve solving problems on the spot or discussing algorithms. Practise on platforms like LeetCode or HackerRank to get comfortable with the types of questions that often come up.
✨Know Your Tools and Frameworks
Make sure we’re well-acquainted with the tools and technologies listed in the job description. Familiarise ourselves with any specific frameworks or programming languages mentioned. If Mozilla Corporation uses React or Node.js, for instance, be ready to discuss how we’ve used them in previous projects or coursework.
✨Showcase Your Projects
Bring along a portfolio that highlights our best work. This could be code samples, GitHub repositories, or any side projects we’ve built. Make sure we can talk through our thought process for each project, especially the challenges we faced and how we solved them—this shows our problem-solving skills in action.
✨Prepare for Behavioural Questions
While technical skills are key, full-time positions also require cultural fit. Be ready to discuss our previous experiences and how we handle teamwork, conflict, and deadlines. Brush up on the STAR method—Situation, Task, Action, Result—to clearly articulate our past experiences when discussing how we've contributed to a team.
