Senior Software Engineer - Wikidata Platform

Summary

The Wikimedia Foundation is seeking a Senior Software Engineer to join the team supporting the Wikidata Platform — the structured data backbone of Wikimedia projects and a key part of the global open knowledge ecosystem. You’ll help scale and sustain the Wikidata Query Service (WDQS) and related platform services that power tools, features, communities, and research efforts across Wikimedia projects and beyond.

This role combines backend engineering and operations ownership. You’ll implement high-scale, production-grade services while ensuring performance, reliability, and maintainability. Working closely with the technical and product leads, you’ll contribute to shaping the future of how the world queries and interacts with structured, linked data.

Important: We are a fully remote team. Your working hours will need to overlap with UTC+1 to UTC-5 time zones to accommodate members of your team around the world. With 14:00 UTC to 17:00 UTC being the team’s overlapping hours.

What You’ll Do

• Design, build, and maintain backend systems and APIs that power Wikidata’s query infrastructure
• Improve reliability, observability, and automation of the Wikidata Query Service and data pipelines
• Integrate Wikidata Platform services with other systems and data sources across Wikimedia
• Collaborate with SRE, data engineers, and product teams to ensure stability and scalability under growing usage
• Monitor production systems, respond to operational incidents, and proactively identify and resolve bottlenecks
• Support platform migrations and system upgrades (e.g., triple stores, streaming ingestion)
• Contribute to deployment automation, CI/CD workflows, and service instrumentation
• Participate in code reviews, design discussions, and technical planning
• Document systems and share knowledge with team members and Wikimedia’s broader technical community

Skills and Experience We’re Looking For

• 5+ years of experience as a backend or platform engineer working on distributed systems or data platforms
• Deep understanding of database and/or knowledge graph representation technologies and standards
• Proficiency in Java, C++, or other systems languages. Ability to set up, scale, and investigate systems is more important than expertise in a particular language.
• Experience building and operating production-grade services with SLOs - good appreciation of scalability, performance, reliability and other non-functionals
• Familiarity with modern observability tools (metrics, logging, tracing)
• Experience in data processing systems such as graph databases, search indexes, or data processing pipelines
• Ability to work collaboratively across disciplines and communicate clearly across technical and non-technical audiences
• A commitment to learning, resilience, and contributing to a mission-driven engineering culture

Nice to Have

• Experience working with knowledge graphs or RDF/SPARQL
• Familiarity with streaming data systems (e.g., Kafka, Flink)
• Comfort with CI/CD pipelines and containerization tools (e.g., Docker, Kubernetes)
• Experience in open source or open knowledge communities
• Familiarity with Wikimedia technologies, Wikidata, or MediaWiki

About the Wikimedia Foundation

The Wikimedia Foundation is the nonprofit organization that operates Wikipedia and the other Wikimedia free knowledge projects. Our vision is a world in which every single human can freely share in the sum of all knowledge. We believe that everyone has the potential to contribute something to our shared knowledge, and that everyone should be able to access that knowledge freely. We host Wikipedia and the Wikimedia projects, build software experiences for reading, contributing, and sharing Wikimedia content, support the volunteer communities and partners who make Wikimedia possible, and advocate for policies that enable Wikimedia and free knowledge to thrive.

The Wikimedia Foundation is a charitable, not-for-profit organization that relies on donations. We receive donations from millions of individuals around the world, with an average donation of about $15. We also receive donations through institutional grants and gifts. The Wikimedia Foundation is a United States 501(c)(3) tax-exempt organization with offices in San Francisco, California, USA.