Senior Software Engineer, Add-Ons

About this role

Build and modernize Mozilla’s addons.mozilla.org platform, including automated moderation pipelines, reviewer tools, and developer-facing features. The role combines Python/Django application development with platform reliability, CI/CD, observability, and engineering-practice improvements.

About the company

Mozilla builds open-source products and technologies, including Firefox, that prioritize privacy, security, and an open internet.

The team

Mozilla Add-ons (AMO), supporting the Add-ons ecosystem, DevHub, reviewer tools, and moderation systems.

Stack

What you'll do

• Deliver features and architectural improvements across automated moderation, Reviewer tools, and DevHub.
• Improve CI/CD pipelines and internal developer platforms for safe, consistent software delivery.
• Establish engineering standards for production readiness, testing, incident response, and documentation.
• Build observability and data-backed insights; help operate services, deployments, and incident response.
• Trace behavior across unfamiliar codebases, asynchronous jobs, data stores, and infrastructure.
• Collaborate with product, design, QA, reviewers, developer support, and community contributors.
• Document designs, architecture decisions, runbooks, and incidents; share knowledge and mentor peers.

What we're looking for

• Strong hands-on experience building and maintaining production applications with Python/Django.
• Experience operating production systems where reliability and safe delivery matter.
• Strong CI/CD experience, including declarative pipelines and infrastructure as code.
• Experience with automated testing, integration testing, and staged or progressive delivery.
• Understanding of observability, including metrics, logs, tracing, SLOs, and actionable alerting.
• Experience with internal tools or platforms and engineering practices such as runbooks, on-call, and incident response.
• Ability to debug complex production issues and trace behavior across frontend, backend, asynchronous jobs, data stores, and infrastructure.
• Strong technical writing, communication, and collaboration skills in distributed teams.

Nice to have

• Google Cloud and Kubernetes experience.
• Infrastructure as code and policy as code.
• SLOs, error budgets, chaos engineering, disaster recovery, or production readiness reviews.
• Trust and safety, automated moderation, or abuse prevention experience.
• Open-source contributions.

Benefits

• Performance-based bonus plan.
• Medical, dental, and vision coverage.
• Retirement contributions with immediate vesting.
• Quarterly company wellness days and a birthday day off.
• One-time home office stipend and quarterly well-being stipend.
• Annual professional development budget.
• Paid parental leave.