Multi-year contract funds a ground-up reengineering of FOLIO’s Electronic Resource Management and Serials modules, modernizing the codebase while moving it from Grails to Go. Index Data will be staying on to maintain the modules once the rewrite is complete

GÖTTINGEN, Germany and COPENHAGEN, Denmark — August 12, 2026 — VZG has awarded Index Data ApS the contract to reengineer FOLIO’s Electronic Resource Management (ERM) and Serials modules — a project the two organizations are calling ERM 2.0. The contract is signed, and work officially begins on August 15, 2026.

VZG is the central office of GBV, the Common Library Network, a consortium of roughly 220 academic and public libraries and research institutions across Germany and beyond. VZG has led development of the FOLIO ERM modules on the network’s behalf since 2018, with around 35 GBV libraries already live on FOLIO ERM and total adoption expected to reach around 50 by the end of 2026. In April 2026, VZG informed the FOLIO community of its plans for the modules’ future and launched a Europe-wide procurement process to find a partner for the next phase. That process has now concluded.

The existing ERM and Serials modules were built in Grails starting in 2018. Under the new contract, Index Data will port them to Go and modernize the underlying architecture, following the FOLIO Technical Council’s technology guidelines and the platform’s broader move toward Eureka, with GOKB remaining the primary source for title and package data. The initial focus is the technical redesign; functional enhancements will be considered along the way, wherever they add real value and fit within the project’s scope. Index Data has been supporting the modules on an interim basis in the lead-up to the contract, and that maintenance will continue without interruption as the reengineering work begins. Once the rewrite (planned over 3 years) is complete Index Data is contracted to stay on and maintain the new ERM 2.0 modules, providing continuity and a stable partnership start to finish.

“This project is a testament to the stewardship that VZG has shown for the FOLIO ERM community, and we’re proud that VZG has entrusted us with it,” said Mike Gorrell, Managing Director of Index Data ApS. “Reengineering, cleaning up technical debt, and adding real value – within scope – are excellent signs for FOLIO sustainability”. 

“Since the beginning VZG has funded the development and maintenance of this important functionality within FOLIO, and we are pleased to continue that work going forward,” said Kirstin Kemner-Heek, Head of Library Management Systems Department at VZG. “Index Data has been a trusted partner of VZG’s since 2019, and has already been maintaining the ERM modules on an interim basis ahead of this contract. We’re glad to be extending that work into a full reengineering.”

The project begins with foundational groundwork in August and September 2026 and is organized into work packages, accounting for dependencies and potential enhancements along the way.. As with the original development of FOLIO ERM, the ERM Special Interest Group will be closely involved throughout, and progress will be shared with the community on an ongoing basis. All resulting code will be published under the Apache License 2.0 in the Open Library Foundation repository. VZG and Index Data plan to share updates as the project moves forward, including at WOLFcon 2026.

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About VZG

VZG is the central office (Verbundzentrale) of GBV, the Common Library Network — a cataloguing and service consortium of around 200 academic and public libraries and research institutions across its member states and the Stiftung Preußischer Kulturbesitz. VZG provides a framework for coordinated library automation across the network and develops new library and information services. It has led development of FOLIO ERM since 2018.

About Index Data

Founded in Copenhagen in 1994, Index Data has helped shape open-source library technology for more than 30 years, serving as the original architects and developers of both the FOLIO Library Services Platform and Project ReShare. The company provides SaaS hosting, implementation, support, and development services to libraries and consortia worldwide. Its work centers on FOLIO, VuFind for patron discovery, and the Library Data Platform (LDP/Metadb) for reporting and analytics. With specialists across four continents, Index Data’s “Partners, not Vendors” ethos runs through all of its engagements.