Knowledge Base Glossary of address terms
Find out the difference between UPRN, USRN and UDPRN and more
Address Element An address element can be any known part of an address which you’d like to validate.
Address Management The process of looking after and updating your address databases over time. This ranges from checking accuracy when you first collect an address to many years later when the address may have changed.
Address Matching A type of address search which uses any combination of parts of the address to find the full and correct result.
Alias Data Data maintained by Royal Mail which contains additional address information not required for postal delivery, such as local place names (i.e. Kensington), historical county names and company trading names.
API An API (which stands for Application Programming Interface) is a set of routines and tools that can be used for building software and applications. Developers often use APIs to gain access to functionality without having to directly develop that functionality themselves. APIs can be considered to be the building blocks that developers use to build software and applications.
Barcode A unique code used for automated mail sorting that is derived from a Delivery Point Suffix and a Postcode. Batch Processing of Address Data Often also called Address Cleaning or Address Cleansing, this is the automated process of updating or correcting addresses.
BS7666 A British standard that (among other things) defines a way to represent addresses and is used by the NLPG database.
Current County A data set developed by Allies which offers a County name for every Postcode in the UK. A complete set of county data and our “Current County” is not available from PAF®.
Data Extract A subset of data from the full data file. For example from a selected Postcode Area, User Category or all addresses within a radius from a centre point. See also Raw Data.
Delivery Point A single letterbox, for example a house or a business.
Delivery Point Suffix A unique code for each Delivery Point in a Postcode.
Dependent Locality A small town or village name sometimes included in an address when the Delivery Point is outside the boundary of the main Post Town that serves it.
Dependent Street Sometimes included in an address when the Delivery Point is not on the main street, for example a shopping arcade off a high street.
Double-Dependent Locality A business park, industrial estate or hamlet which is smaller than a Dependent Locality, sometimes included in an address.
Fuzzy matching Method for matching two phrases that are not 100% the same, mainly used to compensate for spelling mistakes or typos, meaning that when you search for “allys computng” by accident you still find “Allies Computing”.
Geocoding The act of looking up a postcode, address or location to determine its geographic position and other administrative data (see Geodata). A typical scenario would be to “geocode your store addresses” so you can plot them on a website map for your customers.
Geodata Geographical and administrative data such as Grid References, latitude and longitude (in OSGB36 and ETRS89 format), NHS Health Authority codes and names, and Local Authority ward codes and names. These metrics are available through PostCoder for each postcode using data supplied by the Office of National Statistics (ONS).
Grid References Coordinates that reference a geographic location. In PAF® they define the location of the averaged centre point of a Postcode, derived from the Ordnance Survey National Grid.
Incode This is the second part of a Postcode, and is used after the Outcode to sort the mail into a postal delivery “walk”.
IP Address Each machine connected to the Internet has a numeric address known as an Internet Protocol address (IP address). The IP address takes the form of four numbers separated by dots, for example: 184.108.40.206.
Large User A user category that denotes a single delivery point that has been assigned its own Postcode due to the volume of mail it receives.
Local Authority Ward Code Part of GeoData these codes are a six alpha-numeric (Local Authority) or a four alpha-numeric (Unitary Authority) code that denotes the county, Authority and electoral ward of the Postcode. In Northern Ireland, the 6 characters are made up of ‘95’ plus a letter, a space and the electoral Ward.
Multiple Residence An additional data file to PAF® containing approximately 400,000 more addresses at Delivery Point. This data contains information about the addresses behind a single Delivery Point on PAF®, for example, a university Halls of Residence with 5000 residences behind 1 main letterbox.
NHS Health Authority Code A three character code included in GeoData which identifies the Health Authority or board responsible for funding patient care within each Postcode.
NHS Primary Care Trust Codes A three character code for groups of GP practices taken from the Office of National Statistics and included with GeoData.
NLPG The National Land and Property Gazetteer is a database of addresses across England and Wales which is created from data supplied by Local Councils, and based around the BS7666 standard. The Postcodes are the same as in PAF® but the addresses may differ.
NSPD The National Statistics Postcode Directory supplied and maintained by the Office of National Statistics containing geographic information such as Government Offices, National Parks, Census and Electoral areas.
Outcode This is the first part of a Postcode, and is used before the Incode to direct the mail to a sorting office.
PAF® This is Royal Mail’s “Postcode Address File®” which contains all postal addresses in the UK, Channel Isles and Isle of Man.
Pay per click Pricing model whereby each address lookup, defined as a “click”, deducts a fixed number of credits from a pack of credits. Designed to help you pay less, by charging only for what you use. Supported by PostCoder.
PAON Primary Addressable Object Name is an element of NLPG which is the Premise number and/or the Premise name.
Postally Correct An accurate and up-to-date address in the correct format required by Royal Mail for postal purposes.
Postcode This is the primary piece of information used in the sorting and delivery of postal items. A Postcode represents anywhere between one or one hundred Delivery Points, or a PO Box. It has two parts: the Outcode and the Incode. These are further divided into an Area, District, Sector and Unit (see the individual definitions of these terms).
Postcode Area This is indicated by the first letter(s) in the Postcode, for example NR. There are 124 Postcode Areas in the UK.
Postcode District This is a sub region of a Postcode Area represented by the numbers in the Outcode. (Refer to the definition of Postcode). An example of a District is NR14.
Postcode Sector Represented by the first digit of the Incode (Refer to the definition of a Postcode). An example of a Sector is NR14 7.
Postcoder Our flagship API product, developed and tested in house by Allies.
Premise Level PAF® Full addresses containing the individual Delivery Point details, for example the organisation name, department, PO Box number, building name, sub-building name and/or building number, as well as the Thoroughfare level PAF® data.
Raw Data This could be PAF® and/or GeoData or another dataset in a fixed width or csv format. In its original form, the data is supplied as a large, multi-segmented database which we convert into a file that can be easily used with most databases and spreadsheets.
SAON Secondary Addressable Object Name is an element of NLPG which describes a secondary addressable object within PAON, for example, “first floor”.
Thoroughfare Level PAF® An address at street level only, including the Dependent Street, Main Street, Double-Dependent Locality, Dependent Locality, Post Town and Postcode, but not the Delivery Point details.
UDPRN The UDPRN (which stands for Unique Delivery Point Reference Number) is a numeric 8-digit code used by the Royal Mail to identify postal addresses in the UK. Each postal address (also known as a Delivery Point) within the Royal Mail PAF® database has a unique UDPRN. The UDPRN for a Delivery Point remains fixed regardless of any changes in the address itself (e.g. through corrections, company name changes or postcode modifications). UDPRNs are not re-assigned if a Delivery Point is deleted from PAF® but can be re-activated if the original Delivery Point is added back into PAF®.
UPRN Unique Property Reference Number from the National Land and Property Gazetteer.
User Category This indicates whether a Premise is a residential, non-residential or large user address.
USRN Unique Street Reference Number is a field in NLPG that identifies the street. The number is derived from the National Street Gazetteer, which is a countrywide register of streets.
Postcoder address lookup and validation
Postcoder address lookup API by Allies provides the fastest, most reliable way to capture accurate addresses.
Postcoder enables people to use their postcode to lookup and fill in their address. Postcode lookup is up to 80% faster than typing an address manually. Automatic address verification provides addresses that are 100% up to date and postally correct.
Find out more about Postcoder >