Senior Software Engineer, Backend

As a Senior Software Engineer on the Ecosystem Services Team, you’ll build and own back-end systems and the integrations that keep our services running, 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 engineers, product managers, CloudEng, and UX and design partners to deliver reliable features.

We are looking for engineers who treat the systems they build as their own: people who are comfortable owning a service end to end, from writing the code to verifying it works as intended in production and monitoring its health.

We are hiring for multiple Ecosystem Services Team back-end teams - each solving their own unique challenges to make the web better for everyone. More details about all hiring teams will be shared in the interviews.

About Ecosystem Services

Ecosystem Services builds and operates the back-end platforms that power Mozilla products and services, with a focus on privacy, security, and delivering critical functionality to Firefox and millions of users worldwide .

Our portfolio spans a diverse set of platforms and services. Representative examples include Privacy Services, which provides the APIs and infrastructure behind Mozilla VPN, Relay (email and phone aliasing), and Monitor (data breach detection and remediation); AutoPush, Mozilla's Web Push platform for securely delivering notifications and real-time updates to Firefox clients; and Remote Settings, Mozilla's platform for delivering configuration updates to Firefox outside the regular release cycle. Together with many other backend platforms across the organization, these services help deliver secure, reliable experiences to Mozilla users every day.

Our teams own services end-to-end from designing and building distributed systems, to operating them in production, improving reliability, and evolving the cloud infrastructure they run on. We work closely with product, frontend engineering, Cloud Engineering, UX, and design partners to build resilient systems that make the web better for everyone.

We're hiring backend engineers across multiple Ecosystem Services teams, each tackling different technical challenges while sharing a culture of ownership, collaboration, and operational excellence. More details about the specific teams and domains will be shared during the interview process.

What you’ll do:

• Lead backend development, building and maintaining server-side logic
• Take real ownership of the services you work on: deploy them, operate them, and keep them healthy in production rather than handing them off
• Work closely with our CloudEng Team to maintain and improve production environments, including monitoring and alerting with tools such as OpenTelemetry , Sentry , Prometheus , and Grafana
• Participate in an on-call / off-hours support rotation, triaging and resolving production issues, partnering with CloudEng and support teams to investigate incidents, address bug reports, and keep the application running reliably
• Periodically rotate into a support role, handling releases, dependency updates, and incoming work requests from customer support and other stakeholders
• Thoughtfully apply AI-assisted development tools to move faster and raise quality, while maintaining good judgment about where they fit and where they don't
• Partner with and support stakeholders (e.g. front-end, platform), ensuring backend systems, APIs, and data contracts meet their needs
• Partner with frontend and cross-functional teams to align on project goals, contribute to API design, and ensure backend systems, APIs, and data contracts meet their needs
• 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:

• 4+ years of experience in software development with a strong focus on backend technologies
• Strong professional experience with Python , TypeScript/Node.js , or Rust building back-end services and confidence leading back-end engineering projects.
• Proficiency with PostgreSQL and SQL query optimization, including relational schema design and migrations with a query builder such as Knex
• Hands-on DevOps experience on Google Cloud Platform (GCP) , with Docker-based build and deploy pipelines. You are comfortable deploying, operating, and troubleshooting services in the cloud rather than handing that responsibility to someone else
• Hands-on experience with observability and monitoring tooling such as Sentry and Grafana
• A pragmatic commitment to shipping quality work. You care about the quality and reliability of what you ship, you make sensible trade-offs under real constraints, and you consistently move work to and into production.
• Strong engineering judgment. You can navigate ambiguity, weigh trade-offs, and make sound decisions with incomplete information, and you know when to ask for input
• A genuine ownership mindset. You are excited to own a service end to end and have a track record of operating what you build in production, including experience with on-call or off-hours production support
• Experience mentoring junior engineers and driving technical excellence in code quality, testing, and process improvements

Bonus Points for experience with:

• Performance / load testing
• Experience with IaC tools such as Terraform and Kubernetes
• Open-source contributions or personal engineering projects
• Django experience

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 View email address on us.fitly.work 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.