What is a preprint server?

Preprint servers are freely accessible online digital archives for early drafts of research outputs, submitted by the authors (known as self-archiving). Preprint servers may be subject-specific, while others accept submissions covering all areas of research. By posting on preprint servers, authors are able to make their findings available to the scientific community and receive feedback on draft manuscripts before they are submitted to journals. arXiv, bioRxiv, are examples of preprint servers.

Not all preprint servers are created equal, so it is important that you check what your preferred preprint server allows you to upload. Some preprint servers allow accepted manuscripts to be posted (such as arXiv) - others, like bioRxiv, do not allow it.

You can check the REF Open Access policy on preprint servers here.