Key facts

Resolving mechanisms

A central, curated registry stores the information necessary to resolve either URI or CURIE forms of identifier, which are sent as queries to the Identifiers.org resolving system.

URI resolution

Identifiers.org provides direct access to the identified data using one selected physical location (or resource). Where multiple physical locations are recorded in the registry the most stable one is selected for resolution. This allows the location independent referencing (and resolution if required) of data records.

URI resolution pattern: http://identifiers.org/[namespace]/[entity], eg: http://identifiers.org/pdb/2gc4.

CURIE resolution

Identifiers.org is able to handle queries presented as CURIEs (prefixed identifiers). These prefixes may be encoded at the level of individual resources (resolving locations), allowing the location dependent referencing of data. This is useful for publishers, and will be an important means by which specific data providers or resources may be acknowledged.

Namespace CURIE pattern: [namespace prefix]:[accession], eg: pdb:2gc4.

Provider CURIE pattern: [provider code]/[namespace prefix]:[accession], eg: pdbe/pdb:2gc4.

Terms of Use


The Identifiers.org dataset, including individual records and annotations therein, are provided under the terms of the Creative Commons CC4 Attribution license.

Briefly, this means you are entitled to use the data we provide, including sharing, transformation and redistribution thereof, for any purpose, providing that appropriate credit is given, and that any changes are clearly indicated. For full details, please visit the Creative Commons site.


The dataset is provided "as is", without warranty of any kind, express or implied, including but not limited to the warranties of merchantability, fitness for a particular purpose and noninfringement. In no event shall the Identifiers.org Team be liable for any claim, damages or other liability whatsoever, whether in an action of contract, tort or otherwise, arising from, out of or in connection with the dataset or the use or other dealings in the dataset.

Funding bodies

BBSRC logo EMBL logo Open PHACTS logo ELIXIR logo NIGMS logo BMB logo Excelerate logo


SPARQL-enabled identifier conversion with Identifiers.org.
Wimalaratne S., Bolleman J., Juty N., Katayama T., Dumontier M., Redaschi N., Le Novère N., Hermjakob H. and Laibe C.
Bioinformatics (2015) 31 (11): 1875-1877.
Towards the collaborative curation of the registry underlying Identifiers.org.
Juty N., Le Novère N., Hermjakob H. and Laibe C.
Nucleic Acids Research (2013) bat017.
Identifiers.org and MIRIAM Registry: community resources to provide persistent identification
Juty N., Le Novère N. and Laibe C.
Nucleic Acids Research (2012) 40 (D1): D580-D586.
The EBI RDF platform: linked open data for the life sciences.
Jupp S., Malone J., Bolleman J., Brandizi M., Davies M., Garcia L., Gaulton A., Gehant S., Laibe C., Redaschi N., Wimalaratne S., Martin M., Le Novère N., Parkinson H., Birney E., and Jenkinson A.
Bioinformatics (2014) 30 (9): 1338-1339.