Event:Query Service Days 2026
- Welcome!
- The Query Service Days 2026 is an online event focusing on the migration of the Wikidata Query Service from Blazegraph to QLever, and supporting the Wikidata community, tool maintainers and data reusers with adapting their queries and tools to the new endpoint. This event is run in collaboration with the Wikidata team at Wikimedia Deutschland and the Wikidata Platform team at WMF, and aims to ensure that everyone using the Query Service is informed about the next steps and has a space to test the new systems, ask questions, and get support to adapt their queries.
- How does it work?
- The event is taking place online during one week, from October 17th to 23rd, 2026. You will be able to join sessions live, or to watch the replay later on. You will find the schedule below on this page. The sessions take place in English, and are open to everyone using the Wikidata Query Service, regardless of their level of knowledge of SPARQL. You have 3 options to watch the sessions:
- Attend live in the BigBlueButton room: you'll be able to interact with the speakers and other participants. Once you have registered for the event you can find the unique Jitsi link on the Event details page. Note: if you join the BBB room, please be aware that we will be recording the call and broadcasting it live on Youtube.
- Watch the livestream of the sessions on Youtube: great option if your connection or device doesn't support BBB, or if you don't want to appear on the videos. You can find the links for each day on the schedule tables below.
- Watch the replay videos later on Youtube or Wikimedia Commons: to catch up in case you missed the live transmission, you can find the links for each day on the schedule tables below.
- Register to the event
- We encourage you to sign up to the event on this page to receive updates and access links. In order to register, you need to be logged in with your Wikimedia account, and click on the "register for event" button at the top of this page.
- Program
- The event schedule is currently under construction and will be updated on this page in the upcoming weeks. It mostly consists in presentations of the migration plan with Q&As and hands-on sessions so every type of data user can learn how to update their queries and prepare for the migration with confidence.
- Code of conduct
- Please note that the entire initiative, including the presentations and discussions on various channels, is covered by the Code of Conduct for technical spaces. Please contribute in making the discussion spaces safe and welcoming for everyone.
- Discussions and help
- If you have questions or suggestions about the event, feel free to use the talk page. Announcements about the event are talking place on the same talk page, and on the Wikidata Telegram group. If you want to reach out to the organizers directly, feel free to contact Mohammed Abdulai (WMDE) or Sannita (WMF).
Sessions
Saturday, October 17th
Wikidata Query Service is migrating from Blazegraph to QLever. In this session we will give an overview of why we are switching, what is changing, the timelines and what is coming next.
This session is especially for editors who are using Wikidata Query Service as part of their day-to-day work and might not be very proficient in SPARQL.
Slides from Lydia - Slides from Brandon
Speaker(s): Lydia Pintscher (WMDE), BTracy-WMF
Some queries will need to be adapted as part of the migration from Blazegraph to QLever. In this session we will look at cases that need rewriting and show tools available to help you adapt queries.
This session is especially for editors who are using Wikidata Query Service as part of their day-to-day work.
Speaker(s): BTracy-WMF, GModena (WMF)
Some queries will need to be adapted as part of the migration from Blazegraph to QLever. In this session we will adapt some queries together.
This session is especially for editors who are using Wikidata Query Service as part of their day-to-day work.
Speaker(s): BTracy-WMF, GModena (WMF)
UTC 19:00
CEST 21:00
NZT 8:00
Your time zone
⏱️ 50 minutes
Let's play some Wikidata-powered games together!
Facilitation: Lydia Pintscher (WMDE)
Sunday, October 18th
Wikidata Query Service is migrating from Blazegraph to QLever. In this session we will give an overview of why we are switching, what is changing, the timelines and what is coming next.
This session is especially for editors who are using Wikidata Query Service as part of their day-to-day work and might not be very proficient in SparQL.
Slides from Lydia - Slides from Brandon
Speaker(s): Lydia Pintscher (WMDE), BTracy-WMF
Some queries will need to be adapted as part of the migration from Blazegraph to QLever. In this session we will look at cases that need rewriting and show tools available to help you adapt queries.
This session is especially for editors who are using Wikidata Query Service as part of their day-to-day work.
Speaker(s): BTracy-WMF, GModena (WMF)
Some queries will need to be adapted as part of the migration from Blazegraph to QLever. In this session we will adapt some queries together.
This session is especially for editors who are using Wikidata Query Service as part of their day-to-day work.
Speaker(s): BTracy-WMF, GModena (WMF)
Monday, October 19th
Wikidata Query Service is migrating from Blazegraph to QLever. In this session we will give an overview of why we are switching, what is changing, the timelines and what is coming next.
This session is especially for tool builders and reusers who are using Wikidata Query Service as part of their applications.
Speaker(s): Lydia Pintscher (WMDE), BTracy-WMF
The migration from Blazegraph to QLever is a good point in time to consider if you are using the best access method for your usecase. Should you adapt your queries or maybe switch to one of the other data access method Wikidata provides? In this session you will get an overview of the different access methods and what is best for your use case.
This session is especially for tool builders and reusers who are using Wikidata Query Service as part of their applications.
Speaker(s): Lydia Pintscher (WMDE)
A few pioneers have already made the switch to the new QLever-powered Query Service. In this session they will talk about their migration experience.
Slides from Andrew (Scribe) - Slides from Sai (WikiSource Reader)
Speaker(s): AndrewTavis (Scribe), Saiphani02 and Bodhisattwa (Wikisource reader)
Some queries will need to be adapted as part of the migration from Blazegraph to QLever. In this session we will adapt some queries together.
Facilitation: BTracy-WMF
Later during the day...
Tuesday, October 20th
Wikidata Query Service is migrating from Blazegraph to QLever. In this session we will give an overview of why we are switching, what is changing, the timelines and what is coming next.
This session is especially for tool builders and reusers who are using Wikidata Query Service as part of their applications.
Speaker(s): Lydia Pintscher (WMDE), BTracy-WMF
The migration from Blazegraph to QLever is a good point in time to consider if you are using the best access method for your usecase. Should you adapt your queries or maybe switch to one of the other data access method Wikidata provides? In this session you will get an overview of the different access methods and what is best for your use case.
This session is especially for tool builders and reusers who are using Wikidata Query Service as part of their applications.
Speaker(s): Lydia Pintscher (WMDE)
A few pioneers have already made the switch to the new QLever-powered Query Service. In this session they will talk about their migration experience.
Slides from Andrew (Scribe) - Slides from Sai (WikiSource Reader)
Speaker(s): AndrewTavis (Scribe), Saiphani02 and Bodhisattwa (Wikisource reader)
Some queries will need to be adapted as part of the migration from Blazegraph to QLever. In this session we will adapt some queries together.
This session is especially for tool builders and reusers who are using Wikidata Query Service as part of their applications.
Watch it Live on YouTube
Speaker(s): Lucas Werkmeister (WMDE)
Wednesday, October 21st
Some queries will need to be adapted as part of the migration from Blazegraph to QLever. In this session we will adapt some queries together.
This session is especially for editors who are using Wikidata Query Service as part of their day-to-day work and might not be very proficient in SparQL.
Speaker(s): BTracy-WMF, Lucas Werkmeister (WMDE)
Thursday, October 22nd
Bring the Phabricator tickets you really care about and we will improve it together to move it forward.
Facilitation: Lydia Pintscher (WMDE), BTracy-WMF
UTC 9:00
CEST 11:00
NZT 22:00
Your time zone
⏱️ 50 minutes
Let's play some Wikidata-powered games together!
Facilitation: Lydia Pintscher (WMDE)
Later during the day...
Some queries will need to be adapted as part of the migration from Blazegraph to QLever. In this session we will adapt some queries together.
This session is especially for editors who are using Wikidata Query Service as part of their day-to-day work and might not be very proficient in SparQL.
Speaker(s): BTracy-WMF, LErickson-WMF
We will come together and try to figure out some of the harder migration cases together.
Facilitation: BTracy-WMF
Bring the Phabricator tickets you really care about and we will improve it together to move it forward.
Facilitation: Lydia Pintscher (WMDE), BTracy-WMF
Friday, October 23rd
In this session we will wrap up the Query Service Days and recap what's next.
Facilitation: Lydia Pintscher (WMDE), BTracy-WMF
UTC 16:30
CEST 18:30
NZT 5:30
Your time zone
⏱️ 50 minutes
Let's play some Wikidata-powered games together!
Facilitation: Lydia Pintscher (WMDE)
See also
Feel free to add more links here!
🪷 Event useful links
- Main Commons category: Wikidata Query Service Days 2026
- Sessions slides and materials
- Videos
- Collaborative notes (Etherpad)
🖋️ Related documentation pages
- Wikidata:SPARQL query service/WDQS backend update
- Wikidata Query Service/WDQS Architecture re-design
- Query examples and rewrites (more examples and guides are on Wikitech; these are all linked to from the main Migration Guide)
- Query rewriting tool (beta, use with care)
- Request early access
- Query optimization: the QLever version
💬 Telegram and other social media
- Wikidata general Telegram group
- On Mastodon & co: #QueryServiceDays2026