How can local government handle sensitive personal data intelligently without increasing staff workload? Hoeksche Waard Council, working with Conduction and the Open Web Concept, has developed a new solution: source-level anonymisation. This de-identification tool automatically anonymises documents while keeping the text readable.
No more blacked-out sections
Building on the success of their LLM Anonymisation tool (currently being trialled by several councils and suppliers, including Centric), Amanda Hanemaaijer, Information Manager at Hoeksche Waard Council, explains: “Large Language Models help us anonymise more effectively. Most tools either remove text or use black bars, which destroys context and can make information unreadable or even misleading. Our approach replaces names and sensitive details with neutral terms, so the text remains clear and useful.”
Safe and user-friendly
The initial version proved the concept but was too technical for everyday users. With funding from the Innovation Budget (Dutch), the team is now refining the tool. Hanemaaijer says, “It’s great to have this support. We’re focusing on anonymising at the source and improving usability. We wanted to move away from sending sensitive documents to external servers. Now, everything occurs within our own secure environment, making it safer and more efficient. We’ve also added new features, like bulk anonymisation, WCAG accessibility checks, and readability testing. This means the tool not only anonymises but also ensures documents are accessible and easy to understand. ”
Winner Computable Award 2025
Collaborative development
The tool is being developed as part of the Open Webconcept (Dutch), a partnership between councils and private-sector organisations. According to Hanemaaijer, this collaborative approach is the key to its success. “We work open source and share all our knowledge. If one council adds or improves something, everyone benefits. It’s inspiring because we are creating something that moves the entire public sector forward. So, in the coming months, we’ll be working hard to make the tool even more practical for everyday use.”
Wide-ranging applications
Source anonymisation will soon be available for various processes, including requests for information under the Open Government Act (Wet Open Overheid, WOO request), reports, permit applications, and enforcement case files. Hanemaaijer explains: “Any public sector organisation working with documents can use it. Ultimately, anonymisation should become as routine as saving or sharing a file; a standard part of your workflow, without complicated steps.”
The tool will be added to the Nextcloud App Store in 2026, aligning with the Netherlands’ Digitalisation Strategy (NDS).
About the Innovation Budget
The Dutch Ministry of the Interior and Kingdom Relations (BZK) uses the Innovation Budget to encourage collaboration and innovation among government bodies. All Dutch public authorities, provinces, municipalities, water authorities, ministries, and implementing agencies can apply. A new application round opens in March 2026. To see what projects have been realised, visit the YouTube channel (Dutch) featuring explanations from various initiatives.
Source-level anonymisation
Hoeksche Waard Council and the BedrijfsvoeringsPartner (a collaboration of the municipalities of Albrandswaard, Barendrecht, and Ridderkerk) are the initiators, backed by the Open Web Concept movement. Conduction handles the technical design and implementation.
