SOAP is a CrossRef Sponsor. We can provide you with a CrossRef membership, your own DOI prefix and a block of Digital Object Identifiers without having to pay the annual CrossRef membership fees of $275.

A Digital Object Identifier (DOI) is a unique alphanumeric string assigned to a digital object, such as a scholarly article, dataset, or software, to identify and provide persistent access to it. DOIs are managed by organizations such as the International DOI Foundation and are widely used in academic publishing to help ensure reliable and persistent citation of digital works.
Typically, you obtain DOIs through a DOI Registration Agency (RA) like Crossref or Datacite. Registration requires that you pay an annual fee. In the case of Crossref that is $275. Datacite will charge you €2500 annually. On top of that you pay a small extra for each of the DOIs that you register: €0.80 or $1.00 depending on your RA.
Stichting OpenAccess is a Crossref sponsor. Sponsors provide a solution for small organizations who want to register metadata for their research and participate in Crossref but that are not able to join directly due to financial, administrative, or technical barriers. The Crossref sponsor has become the primary route to membership for emerging markets and small or academic-adjacent publishing operations.
Some authors or publishers only need one or a few DOIs for a specific book or a small book series. We provide, in this case, the DOIs for free IF you allow us to include a copy of the book or the series in BookRxiv, an open repository for book publications in the arts, architecture, built environment and design. The DOI will link to the version in the BookRxiv. Because of the licence we use (CC-BY), you can share or upload the book(s) anywhere you like besides the BookRxiv.
We also provide DOIs for the journals we support and publish. In such a case we seek a solution that works for both sides. For instance: when an organisation is now paying an annual fee $275 we offer to sponsor the journal, to host the digital version in Open Journal Systems (OJS) and to provide the required number of DOIs for an all-in-one fee of €249: Crossref membership, prefix, DOIs and hosting in OJS.
You may have your own journal system or repository and just need DOIs. In this case we can provide yearly blocks of DOIs: 10, 20, 50, 100, 200 or 500 DOIs.