Senior Software Engineer, Add-Ons

Mozilla

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

Posted 9/15/2026full-timeRemote • United KingdomSenior💰 £66,000 - £87,000 per yearWebsite

Core Competencies

Role fit

Core Competencies

Use this summary to align your resume positioning with the role.

Demonstrates expertise in building and maintaining production applications using Python/Django, with a strong focus on CI/CD practices and observability. Capable of improving engineering standards and fostering collaboration within distributed teams.

Highest-signal resume keywords

Python/Django DevelopmentCI/CD Pipeline ImprovementObservability and MonitoringTechnical WritingCollaboration in Distributed Teams

ATS Keywords

Tailor your resume

Applicant Tracking System Keywords

Tip: use these terms in your resume and cover letter to boost ATS matches.

Hard Skills

Production Application DevelopmentAutomated Testing WorkflowsInfrastructure as CodeDebugging Complex IssuesCode Review StandardsAsynchronous ProcessingMetrics and LoggingService-Level ObjectivesIncident ResponseRunbook Creation

Soft Skills

CollaborationCommunicationMentoringKnowledge SharingFeedback Provision

Tools & Technologies

MySQLReactTypeScriptGoogle CloudKubernetes

Industry Keywords

Production ReadinessTrust and Safety SystemsAutomated ModerationChaos EngineeringDisaster Recovery Testing

Tech Stack

Tools & technologies

CloudDjangoKubernetesMySQLPythonReactTypeScript

About the role

Key responsibilities & impact

Deliver 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
Provide peer feedback, share knowledge, and help others grow
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, and community contributors on end-to-end improvements
Contribute through pull requests, code reviews, and discussions
Develop features such as submission flows, trust and safety signals, and DevHub and Reviewer tools modernization
Work with Python/Django, MySQL, React/TypeScript, and asynchronous processing systems
Create internal developer platforms and paved paths for safe, consistent software delivery
Contribute to team ceremonies and process improvement
Support deployments, monitoring, and incident response for platform reliability

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 treating pipelines and infrastructure declaratively 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 other 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 read and understand unfamiliar codebases and trace application behavior across frontend, backend, asynchronous jobs, data stores, and infrastructure
Experience debugging complex production issues and turning findings into lasting system improvements
Strong technical writing skills, including design documents, ADRs, runbooks, and incident reports
Experience working iteratively with a visible backlog, regular 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 values: welcoming differences, being relationship-minded, practicing responsible participation, and having grit
Bonus: Google Cloud, Kubernetes, infrastructure-as-code, policy-as-code, SLOs, error-budget reliability practices, chaos engineering, disaster recovery testing, production readiness reviews, trust and safety systems, automated moderation, abuse prevention, and open-source contributions

Benefits

Comp & perks

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)