Senior Software Engineer, MediaWiki

The Wikimedia Foundation is looking for a Senior Software Engineer to join the MediaWiki Platform team. This role involves designing, improving, and maintaining key parts of the MediaWiki stack while driving technical quality and operational excellence to support the foundation's mission of providing free knowledge.

Responsibilities:

• 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
• 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