Wikidata Platform Backend Migration Specialist

The Wikimedia Foundation is a nonprofit organization that operates Wikipedia and other free knowledge projects, supporting a global open knowledge ecosystem. As a Wikidata Platform Backend Migration Specialist, you will support the transition of the Wikidata Query Service to a new backend by analyzing, rewriting, and documenting SPARQL queries. The role focuses on minimizing disruption for editors, developers, and researchers during this critical platform migration.

The Wikimedia Foundation is seeking a contract Wikidata Platform Backend Migration Specialist to support a major backend migration of the Wikidata Query Service. This role contributes directly to the long-term sustainability of Wikidata by helping transition queries away from Blazegraph-specific behavior toward standards-compliant SPARQL 1.1. The specialist will work closely with platform engineers and the global Wikidata community to ensure a smooth and well-documented migration.

Responsibilities:
- Review existing Wikidata Query Service example and community queries for Blazegraph-specific dependencies.
- Identify non-standard query patterns and assess their impact on the new backend.
- Rewrite affected queries to be compatible with SPARQL 1.1 standards.
- Develop and document canonical rewrite patterns for deprecated query constructs.
- Support the Wikidata community through guidance, documentation, and direct assistance.
- Surface recurring issues and migration risks to the platform engineering team.

Requirements:
- Strong hands-on experience with SPARQL, including SPARQL 1.1.
- Experience working with large or complex RDF datasets.
- Background in data platform migrations or deprecating legacy systems.
- Ability to understand, refactor, and improve real-world queries written by others.
- Strong technical writing and documentation skills.
- Ability to work independently while coordinating with distributed stakeholders.

Benefits:
- Fully remote contract engagement.
- Flexible working hours with defined UTC overlap.
- Opportunity to contribute to global open knowledge infrastructure.
- Collaboration with an international open source community.

This contract role runs part-time over several months and plays a key role in a high-impact platform transition.