Senior Software Engineer, Add-Ons

Mozilla

. Develop major features and architectural improvements across the Add-ons stack, including automated moderation pipelines, Reviewer tools, and DevHub .

Posted 9/15/2026full-timeRemote • SpainSenior💰 €58,000 - €77,000 per yearWebsite

Core Competencies

Role fit

Core Competencies

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Demonstrates expertise in building and maintaining production applications with Python/Django, while ensuring reliability and safe delivery through CI/CD practices and observability. Strong technical writing and collaboration skills are essential for effective communication and knowledge sharing within distributed teams.

Highest-signal resume keywords

Python/Django Application DevelopmentCI/CD Systems and Declarative PipelinesObservability and MonitoringTechnical Writing and DocumentationCollaboration in Distributed Teams

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Applicant Tracking System Keywords

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Hard Skills

Production Application DevelopmentAutomated Testing and Deployment WorkflowsInfrastructure as CodeDebugging Complex Production IssuesCode Review StandardsOperational ReadinessIncident ResponseMetrics and LoggingTracing and Service-Level ObjectivesAsynchronous Job Management

Soft Skills

CollaborationCommunicationMentoringKnowledge SharingRelationship-Mindedness

Tools & Technologies

Google CloudKubernetesChaos Engineering ToolsPolicy-as-Code ToolingInternal Developer Platforms

Industry Keywords

Automated ModerationTrust and Safety SignalsProduction Readiness ReviewsDisaster Recovery TestingOpen-Source Contributions

Tech Stack

Tools & technologies

CloudDjangoKubernetesPython

About the role

Key responsibilities & impact

Develop major features and architectural improvements across the Add-ons stack, including automated moderation pipelines, Reviewer tools, and DevHub
Establish and maintain engineering standards for code review, production readiness, runbooks, incident response, on-call practices, coding conventions, and infrastructure as code
Create robust observability systems and data-backed insights
Build and improve systems that enable safe development, deployment, observation, and operation of production services
Improve CI/CD pipelines using declarative, pipeline-as-code approaches
Deliver work iteratively through visible backlogs, short feedback cycles, retrospectives, and stakeholder demonstrations
Write technical documentation including design notes, Architecture Decision Records, runbooks, and incident write-ups
Trace requests and asynchronous jobs across unfamiliar codebases to understand failures and identify improvements
Collaborate with designers, product managers, QA, community contributors, engineers, reviewers, developer support, and Add-ons leadership
Contribute through pull requests, code reviews, and open discussions
Work on submission flows, trust and safety signals, DevHub and Reviewer tools modernization, internal developer platforms, team process improvements, engineering standards, deployments, monitoring, and incident response

Requirements

What you’ll need

Strong hands-on experience building and maintaining production applications with Python/Django
Experience operating and improving production software systems where reliability and safe delivery matter
Strong experience with CI/CD systems and declarative pipelines and infrastructure as code
Experience designing or improving automated testing and deployment workflows, including integration testing and staged or progressive delivery
Strong understanding of observability, including metrics, logging, tracing, service-level objectives, and actionable alerting
Experience building or maintaining internal tools or platforms used by engineering teams
Experience defining or improving engineering practices such as code review standards, operational readiness, runbooks, incident response, on-call expectations, or definitions of done
Ability to understand unfamiliar codebases and trace behavior across frontend, backend, asynchronous jobs, data stores, and infrastructure
Experience debugging complex production issues and implementing lasting system improvements
Strong technical writing skills, including design documents, ADRs, runbooks, and incident reports
Experience working iteratively with a visible backlog, stakeholder feedback, and retrospectives
Strong collaboration and communication skills in a distributed team environment
Willingness to share knowledge and mentor peers in operational and reliability practices
Commitment to Mozilla’s values: welcoming differences, being relationship-minded, practicing responsible participation, and having grit
Bonus: Google Cloud, Kubernetes, infrastructure-as-code and policy-as-code tooling, SLOs and error-budget practices, chaos engineering, disaster recovery testing, production readiness reviews, trust and safety or automated moderation, and open-source contributions

Benefits

Comp & perks

Generous performance-based bonus plans to all eligible employees
Rich medical, dental, and vision coverage
Generous retirement contributions with 100% immediate vesting
Quarterly all-company wellness days
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 including life/AD&D, disability, and EAP, varying by country