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Uniform Resource Identifier (URI)

Each occupation, knowledge, skill and competence in ESCO is identified by a string of characters that follows a specific syntax: the Unique Resource Identifier (URI).

A URI is a crucial component of the Semantic Web. Each URI:

  • is unique over the web (universal);
  • allows data from different sources to link to it;
  • is persistent (see ‘backward compatibility’ below for more information).


In the same way as a web address link (URL), if a URI is inserted in a browser, it points to the website where the resource is located. However, the difference between them lies in the fact that the URI is machine-readable.