Senior Software Engineer

Summary

Join the Wikimedia Foundation's MediaWiki Interfaces team as a Senior Software Engineer and contribute to the platform powering Wikipedia and its sister projects. You will design, develop, and maintain key parts of the MediaWiki stack, driving technical quality and operational excellence. This role requires strong experience in software engineering, proficiency in PHP and JavaScript, and a deep understanding of software architecture. You will lead by example, mentor teammates, and collaborate with product and community teams. The position is fully remote, with working hours overlapping UTC+2 to UTC-7 time zones. This is a unique opportunity to combine technical expertise with a mission-driven impact.

Requirements

• Commitment to the Foundation's Mission and Values
• Extensive experience in software engineering, ideally in high-impact web platforms and/or open-source
• Good understanding of HTTP
• Proficiency in PHP and JavaScript
• 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

Responsibilities

• Designing, developing, 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
• Contributing to the adoption and advocacy of API-first development, and influencing best practices in system design, SLOs/SLAs, and OpenAPI Specification
• Championing product metrics: ensuring that key user journeys are instrumented and monitored to guide decisions and 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 user and contributor needs
• Coaching and mentoring teammates to support continuous growth and confidence in both technical and interpersonal skills

Preferred Qualifications

• Experience developing frameworks (designing for reuse, extensibility, stability, and backward compatibility)
• 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 with developer experience tooling, public APIs, or platform teams
• Experience working in a remote, distributed team