Full-Time Senior Software Engineer

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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.

About this team and role: The Relay Engineering Team is committed to building tools that empower users to manage their online identities and maintain their privacy. We work on various ongoing and upcoming projects, ranging from sustaining existing products to integrating new solutions for scalability and security. We are a highly collaborative team that thrives on innovation, feedback, and continuous improvement. As a Senior Software Developer at Mozilla, you will be an integral part of the Relay Engineering Team, responsible for building and maintaining key backend systems and supporting frontend implementations.

What you’ll do:

• Lead backend development when required, in python with Django and REST framework
• Design, implement, and maintain code for email and phone number masking using AWS and Twilio APIs, focusing on security and privacy, in alignment with Relay’s core objectives.
• Work closely with our SRE team to develop and operate production environments including monitoring and alerting with tools such as Grafana, Sentry, and BigQuery to track metrics, tracebacks, and data insights.
• Periodically rotate into a Base Load Engineer (BLE) role: handling releases, dependency updates, and incoming work requests, including bug reports and queries from our customer support team.
• Support frontend development in JavaScript, Typescript, React, and next.js
• 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 that all data protection measures, including email alias management and phone number masking, meet compliance standards.

What you’ll bring:

• 7+ years of experience in software development with a strong focus on backend technologies.
• In-depth knowledge of Python, Django, and confidence leading back-end engineering projects.
• Experience deploying and operating applications on cloud infrastructure like AWS or GCP, with a strong understanding of DevOps practices and SRE collaboration.
• Experience with monitoring tools such as Grafana, Sentry, and BigQuery, including data-driven optimization and troubleshooting.
• Experience with JavaScript, Typescript, React, next.js, SCSS, and a willingness to contribute to full-stack development when needed.
• 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:

• REST API servicing millions of clients
• Twilio
• AWS: SES, S3, SNS, SQS
• GCP: Kubernetes, Compute, SQL, BigQuery
• Email tech: DMARC, SPF, DKIM, FBL

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