UPRN stands for Unique Property Reference Number and was created by the Ordnance Survey (OS). It consists of numbers of up to 12 digits in length. Local governments in the UK have allocated a unique number for each land or property.
A UPRN will consist of comprehensive data of a property, from the planning stages to demolition.
The UPRN stays unique to each property and will remain in it's existing format. Any information added will be linked to matching records in different databases.
Contact your local authority responsible for maintaining addresses to get a UPRN, or use the government local council checker.
A data to retrieve UPRN API is available from Ordnance Survey's AddressBase.
UDPRN is a unique premise identifier produced by Royal Mail in conjunction with the Postcode Address File. This code is readily available with PAF and you can find out more about it here.
Some key differences are:
Despite these differences UDPRN and UPRN essentially perform similar functions. Providing a unique identifying number that lives and dies with a specific property in their respective datasets.