Compact Identifiers (CURIEs)

Examples                         PDB:2gc4
                               Taxon:9606
                                 DOI:10.5281/ZENODO.1289856
                                 ark:/47881/m6g15z54
                                IGSN:SSH000SUA

General format                Prefix:LocalId

Registry links      -> full set of N2T prefix records
                    -> joint N2T/Identifiers.org prefix list
                    -> request to add a prefix to the list
Early adoption      -> Nature Scientic Data: On the road to robust data citation
Formal support      -> Memorandum of Understanding Between CDL and EMBL-EBI

How they work

N2T.net is a kind of URL shortener for persistent identifiers. The above compact identifiers, also known as CURIEs (Compact URIs). They become actionable when appended to a URL based at N2T.net:

https://n2t.net/PDB:2gc4
https://n2t.net/Taxon:9606
https://n2t.net/DOI:10.5281/ZENODO.1289856
https://n2t.net/ark:/47881/m6g15z54
https://n2t.net/IGSN:SSH000SUA

Besides storing and resolving individual identifiers, N2T.net also stores resolution rules for entire classes, based on the prefixes. Failing to find a match after looking up an individual identifier, N2T looks for a rule associated with the identifier's prefix. Rules for the above identifiers result in the following redirects, respectively:

> http://www.rcsb.org/pdb/explore/explore.do?structureId=2gc4
> http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&id=9606
> https://zenodo.org/record/1289856
> http://bibnum.univ-lyon1.fr/nuxeo/nxfile/default/49e1576c-0cae-4b4b-a63b-73370f476681/blobholder:0/THm_2014_NGUYEN_Marie_France.pdf
> https://app.geosamples.org/sample/igsn/SSH000SUA

There is a formal agreement between Identifiers.org and N2T.net to serve a common set of prefixes. You can read more about this effort and our plans to reach out to publishers to encourage adoption of inline citation of compact identifiers in Uniform Resolution of Compact Identifiers for Biomedical Data.