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The Wikimedia Foundation is looking for a Senior Software Engineer to join the MediaWiki Platform team. MediaWiki is the open-source platform that powers Wikipedia and its sister projects - impacting hundreds of millions of Wikipedia users across the globe. The MediaWiki Platform team builds and maintains the core of MediaWiki as well as the components responsible for authentication, notifications, and media management. The team's mission is to provide a solid foundation for feature teams to build on. It focuses on performance, reliability and scalability, helping to ensure broad and equitable access to free knowledge. This role offers a unique opportunity to combine technical depth with mission-driven impact. As a Senior Engineer, you will not only write robust code but also lead by example, prioritize high-impact work, support better decision-making through metrics and observability and foster a culture of accountability, transparency, and continuous improvement.
Job Responsibility:
Designing, improving, and maintaining key parts of the MediaWiki stack
Driving technical quality and operational excellence by defining and reinforcing standards in testing, observability, and system reliability
Comfortably and autonomously creating proofs of concept, writing design documents, and breaking down complex projects into actionable tasks to support less experienced team members
Developing and improving shared capabilities (e.g., authentication, caching, rate limiting) that enable other teams to build efficiently and consistently
Championing key product metrics by focusing on measurable outcomes that guide our decisions and help us to evaluate success
Leading by example in code review, decision-making, and team culture - fostering transparency, empathy, and collaboration
Improving and automating processes for identifying, tracking, and resolving production issues
Collaborating with the Product team and the community to ensure technical solutions align with WMF strategy, feature teams and volunteer contributor needs
Coaching and mentoring teammates to support continuous growth and confidence in both technical and interpersonal skills
Requirements:
Commitment to the Foundation's Mission and Values
Extensive experience in backend software engineering
Familiarity with platform or infrastructure products that serve internal or external engineering teams
Experience with databases and event streams, including schema design, query optimization, and efficient data access patterns
Deep understanding of software architecture, testing methodologies, and system design
Strong experience in observability practices: setting up metrics, logging, monitoring, and alerting
Familiarity with incident response, root cause analysis, and follow-up processes
Experience working with CI/CD pipelines and automated test infrastructure
Nice to have:
Experience developing frameworks (designing for reuse, extensibility, stability, and backward compatibility)
Proficiency in PHP and JavaScript
Familiarity with identity management, including OAuth
Experience with Kubernetes ecosystem, including Envoy
Experience with Prometheus and Grafana
Experience defining and working with SLAs/SLOs or other production reliability frameworks
Prior experience with MediaWiki or Wikimedia projects
Contributions to open-source software
Experience working in a fully remote, distributed team