The ELN Format for the exchange of research data between different open source projects

The ELN file format [1], developed by the ELN Consortium [2]–a group of more than six members representing different open-source electronic lab notebooks (ELNs)–is designed to enable long-term interoperable data exchange between ELNs. It is a dialect of RO-Crate [3], which inherently supports rich metadata to capture documentation, provenance, and associated data files. In contrast to formats like BagIt, which focus on reliable transfer of research data, RO-Crate uses JSON-LD to support semantic data representation. Built on top of schema.org, RO-Crate balances a set of defined properties with flexibility–essential for data management projects that span diverse research domains, that evolve as technology does. Additionally, RO-Crate offers several validators to help identify implementation inconsistencies across tools, facilitating interoperability. As a lightweight, open-source data package tailored for ELNs, the ELN format can be integrated into various workflows for data exchange, not only among ELNs, but also with external infrastructures and research applications. Researchers often rely on storage solutions beyond those natively provided by ELNs. Being able to link raw, processed, or analyzed data directly to documentation supports better organization and contributes to a more complete representation of research. For example, a workflow could connect the research data management platform Coscine [4] with ELNs, such as eLabFTW [5] or PASTA-ELN [6]. In this setup, selected files are automatically (a) transferred to Coscine, (b) linked to the corresponding ELN documentation, and (c) annotated with a basic metadata set to improve searchability and findability within Coscine. The connection is managed natively on both ends, ensuring robustness and long-term maintainability. The metadata link is included in the .eln file, following the RO-Crate specification, and naturally includes domain-specific metadata as needed. Our contribution will focus on two key parts: (1) A description of the ELN file format and the lessons learned in developing a common standard across six different open-source ELN software tools in the research domain, and (2) a demonstration of how this format can be applied to enable seamless information exchange between ELNs and external infrastructure systems. We will therefore show how various developments and tools in the realm of RDM contribute to data efficient and contextualized data exchange.