Senior Software Engineer, MediaWiki Summary
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 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.
Important: We are a fully remote team. 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;
Championing key product metrics by focusing on measurable outcomes that guide our decisions and help us to evaluate success;
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.
Qualities we are looking for:
Accountable: You own your work end-to-end and help establish a culture of responsibility and follow-through;
Commitment to the Foundation's Mission and Values ;
Extensive experience in backend software engineering;
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;
Proficiency in PHP and JavaScript;
Prior experience with MediaWiki or Wikimedia projects;

📌 Senior Software Engineer JS (España)
🏢 Wikimedia Foundation
📍 España