Senior Software Engineer

Role Description

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, focusing on performance, reliability, and scalability.

This role offers a unique opportunity to combine technical depth with mission-driven impact. As a Senior Engineer, you will:

• Design, improve, and maintain key parts of the MediaWiki stack.
• Drive technical quality and operational excellence by defining and reinforcing standards in testing, observability, and system reliability.
• Comfortably and autonomously create proofs of concept, write design documents, and break down complex projects into actionable tasks to support less experienced team members.
• Develop and improve shared capabilities (e.g., authentication, caching, rate limiting) that enable other teams to build efficiently and consistently.
• Champion key product metrics by focusing on measurable outcomes that guide our decisions and help us evaluate success.
• Lead by example in code review, decision-making, and team culture, fostering transparency, empathy, and collaboration.
• Improve and automate processes for identifying, tracking, and resolving production issues.
• Collaborate with the Product team and the community to ensure technical solutions align with WMF strategy, feature teams, and volunteer contributor needs.
• Coach and mentor teammates to support continuous growth and confidence in both technical and interpersonal skills.

Important: We are a fully remote team. Your working hours will need to overlap with UTC-2 to UTC+3 time zones to accommodate members of your team around the world.

Qualifications

• Clear communicator: You explain complex ideas simply and foster shared understanding across engineering, product, and non-technical audiences.
• Outcome-oriented: You prioritize work that delivers value to users and aligns with organizational goals, balancing ideal solutions with constraints.
• Accountable: You own your work end-to-end and help establish a culture of responsibility and follow-through.
• Candid and respectful: You offer feedback directly, constructively, and with care, supporting growth by challenging ideas, not people.
• Collaborative leadership: You inspire trust and progress through support, example, and thoughtful contributions.

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.

Additionally, we’d love it if you 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.

Benefits

• Competitive and equitable salaries.
• Remote-first organization with staff members based in 40+ countries.
• Support for a diverse workforce and an inclusive workplace.