Senior Software Engineer, MediaWiki

The Wikimedia Foundation is looking for a Senior Software Engineer to join the MediaWiki Platform team. This role offers a unique opportunity to combine technical depth with mission-driven impact, focusing on building and maintaining the core of MediaWiki, ensuring performance, reliability, and scalability.

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