What is zenodo

Overview: What is Zenodo?

Zenodo is a multidisciplinary, open-access repository developed under the European OpenAIRE program and operated by CERN, the European Organization for Nuclear Research. Launched in 2013, Zenodo represents a commitment to open science and provides a free platform for researchers, scientists, and academics to deposit, preserve, and share their research outputs. Unlike specialized repositories that focus on specific disciplines, Zenodo accepts research papers, datasets, research software, reports, presentations, posters, and any other research-related digital artifacts from all fields of study.

The platform was commissioned by the European Commission to support the Open Data and Open Access movements in Europe. It operates as a public good, without subscriptions or paywalls, ensuring that research is accessible to everyone regardless of institutional affiliation or geographic location. For each submission, Zenodo automatically mints a persistent digital object identifier (DOI), which makes research outputs uniquely identifiable and citable according to international standards.

Core Features and Capabilities

Zenodo's primary function is to provide permanent digital preservation of research outcomes. Each record receives a unique DOI, typically in the format of 10.5281/zenodo.XXXXXXX, which serves as a stable link to the research output even if the original web address changes. This is critical for long-term preservation and citation accuracy in the scientific record.

The platform supports multiple file formats and content types. Researchers can upload datasets in any format (CSV, NetCDF, HDF5, etc.), software code repositories, preprints, peer-reviewed articles, and supplementary materials. Individual file uploads are limited to 50 GB, accommodating large scientific datasets commonly used in fields like astronomy, physics, earth sciences, and computational biology. Zenodo also allows versioning of records, enabling researchers to upload updated versions while maintaining links to previous versions.

Metadata management is a cornerstone of Zenodo's functionality. When depositing research, users provide structured metadata including title, authors, description, keywords, publication date, and license information. This metadata follows international standards (Dublin Core and other conventions), ensuring interoperability with other research discovery systems and databases worldwide.

Access control is flexible on Zenodo. Researchers can choose to make their work immediately open access or embargo it for a specified period before public release. This feature is particularly valuable for researchers working with sensitive data or those managing publication timelines. Licensing is also customizable, with options ranging from fully open Creative Commons licenses to more restrictive institutional licenses.

Infrastructure and Data Preservation

Zenodo's reliability stems from CERN's world-class digital infrastructure. All files uploaded to Zenodo are stored in CERN's EOS (Experiment Operating System) service, which manages a 5-petabyte disk cluster specifically designed for long-term preservation. The infrastructure includes redundancy and fault tolerance mechanisms critical for institutional repositories.

The preservation strategy employed by Zenodo includes both online and offline components. Daily incremental backups of the entire EOS storage cluster are automatically performed and transferred to a Ceph storage cluster located in a different geographical region. This geographic distribution protects against data loss from localized incidents such as natural disasters or infrastructure failures. Additionally, CERN maintains offline copies of critical data to ensure preservation across technological transitions—a practice known as "bit preservation."

Zenodo's infrastructure has proven capable of scaling. As of 2021, the platform had accumulated over 1 petabyte of research data across its 15 million records. The system has processed over 45 million unique views and 55 million unique downloads, demonstrating its role as a major hub in the global research infrastructure. These figures highlight the platform's significance for research discovery and dissemination.

Research Use Cases and Statistics

Zenodo supports diverse research communities. In physics, researchers deposit large datasets from particle accelerator experiments and astronomical surveys. Environmental scientists upload climate models, satellite imagery, and field measurements. Social scientists contribute survey datasets and qualitative research materials. Medical researchers deposit clinical trial data and genomic sequences. This multidisciplinary approach distinguishes Zenodo from specialized repositories and makes it a comprehensive platform for all research types.

The platform's growth reflects increasing adoption of open science principles. From its 2013 launch through 2021, Zenodo grew to host 15 million items—a trajectory demonstrating strong research community engagement. Annual visitor statistics of 15 million visits (as of 2021) place Zenodo among the world's most-used research platforms.

Funding agencies increasingly require data deposit in platforms like Zenodo as a condition of research funding. The European Union's Horizon Europe program, for example, mandates open access to research data for many projects. This regulatory environment has accelerated Zenodo's adoption and usage growth.

Common Misconceptions About Zenodo

Misconception 1: Zenodo is only for physics research. While Zenodo originated from CERN, it is genuinely multidisciplinary. The platform accepts research outputs from all fields including social sciences, humanities, engineering, medicine, and environmental science. The prominent physics presence reflects CERN's origins, but the infrastructure supports the entire research ecosystem.

Misconception 2: Data on Zenodo isn't truly preserved—it could disappear at any time. This misunderstands the preservation model. CERN operates Zenodo as a long-term institutional commitment backed by European funding. The platform implements industry-standard preservation practices including geographic redundancy, offline backups, and regular integrity checking. The infrastructure and governance model provide substantially more preservation assurance than most institutional repositories.

Misconception 3: Zenodo is primarily for already-published articles. While preprints and published papers are common, Zenodo equally supports unpublished datasets, code, and other research outputs. Many researchers use it primarily to deposit raw data or software without associated publications. This flexibility makes it valuable at all stages of the research lifecycle.

Misconception 4: Depositing to Zenodo prevents journal publication. In fact, Zenodo deposits typically enhance publication prospects. Most journals explicitly allow preprint deposition and data sharing through Zenodo. Publishers and funders increasingly expect supplementary data to be available in open repositories. Zenodo use supports rather than hinders publication workflows.

Practical Considerations and Best Practices

For researchers considering Zenodo deposit, several practical steps apply. Creating an account is free and requires only an email address. The deposit interface is intuitive, guiding researchers through metadata entry, file upload, and license selection. DOI assignment happens automatically upon deposit, typically within minutes.

Choosing appropriate metadata is crucial. Detailed, structured metadata improves discoverability and research impact. Including keywords, funder information, and related publication citations helps connect different research outputs. Zenodo's metadata schema aligns with major research data standards, enhancing interoperability.

License selection carries legal implications. Creative Commons licenses (CC BY, CC0, etc.) are recommended for maximum openness. Researchers unfamiliar with licensing should consult their institution's guidelines or use standard options provided by Zenodo. Clear licensing prevents future confusion about permitted reuse.

Versioning practices deserve attention. When researchers update datasets or code, they should document changes in new versions while maintaining links to previous versions. This practice supports research reproducibility and allows citing specific dataset versions in methods sections of papers.

Communities and collections within Zenodo help organize related research. Many research groups, institutions, and projects maintain Zenodo communities. Contributing to relevant communities increases visibility and connects research with similar work in the field.