Senior Software Engineer

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, and Pocket, a service for keeping up with the best content online. 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

The Firefox Monitor Engineering Team builds tools that help people understand and respond to data breaches. We notify users when their credentials appear in exposed datasets and empower them to take back control of their online privacy. We operate at scale, serving millions of users, and our work sits at the intersection of security, data privacy, and product engineering.

As a Senior Software Engineer on the Firefox Monitor team, you will be a core contributor to a modern, cloud-native Node.js/TypeScript full-stack application. This role spans feature development, infrastructure ownership, and application support. You'll own backend systems and integrations that keep users informed and protected, help maintain and evolve the cloud infrastructure the application runs on, and play an active role in keeping the service reliable and healthy in production. You'll do this while collaborating closely with frontend, SRE, and product teams to deliver reliable, privacy-first features.

What you’ll do: 

• Lead backend development in Node.js and TypeScript, building and maintaining server-side logic within a Next.js full-stack architecture
• Design, implement, and maintain integrations with external data sources such as Have I Been Pwned (HIBP) and other breach intelligence providers, with a focus on data privacy and security
• Build and maintain event-driven systems using Google Cloud Pub/Sub, and own cloud infrastructure on GCP ( GKE) and AWS (S3, SES)
• Own and evolve the data layer, including PostgreSQL schema design and query optimization using Knex, and Redis caching strategies
• Work closely with our SRE team to maintain and improve production environments, including monitoring and alerting with OpenTelemetry, Sentry, Prometheus, and Grafana
• Triage and resolve production issues, partnering with SRE and support teams to investigate incidents, address bug reports, and keep the application running reliably
• Periodically rotate into a Base Load Engineer (BLE) role, handling releases, dependency updates, and incoming work requests from customer support and other stakeholders
• Partner with and support the frontend team in their work with React, TypeScript, Next.js, and SCSS, ensuring backend systems, APIs, and data contracts meet their needs
• Partner with cross-functional teams to align on project goals, ensure seamless frontend-backend integration, and contribute to API design and evaluations
• Participate in code reviews to maintain high standards of code quality and system reliability
• Participate in security and privacy reviews, ensuring all data protection measures meet compliance standards

What you’ll bring: 

• 7+ years of experience in software development with a strong focus on backend technologies
• Deep expertise in Node.js and TypeScript, with experience building and leading backend engineering projects
• Proficiency with PostgreSQL and SQL query optimization; experience with query builders such as Knex is a plus
• Experience deploying and operating applications on GCP (Cloud Run, Pub/Sub, Cloud Logging) with a solid understanding of DevOps and SRE collaboration
• Experience with AWS (S3) or similar cloud storage services
• Hands-on experience with observability tooling including OpenTelemetry, Sentry, Prometheus, and Grafana
• Familiarity with Redis for caching and session management
• Experience with Next.js, React, and SCSS, with a willingness to contribute to full-stack development when needed
• Experience with modern testing practices including unit testing (Vitest), end-to-end testing (Playwright), and component testing
• Strong communication skills and ability to collaborate across engineering, product, and operations teams
• Experience mentoring junior engineers and driving technical excellence in code quality, testing, and process improvements

Bonus Points for experience with

• Stripe or payment platform integrations
• Mozilla Fluent or other i18n/l10n frameworks
• Storybook for component-driven development
• Performance/load testing 
• Data breach intelligence or cybersecurity domain knowledge

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.

Group: D

Req ID: R3082