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This endpoint returns one or more Royal Mail Not Yet Built addresses for a given UK postcode.

Not Yet Built: Enable access on your API key using the Features page or by contacting us.

Request URL


Path parameters

apikeyYour API keyPCW45-12345-12345-1234X
postcodeThe URL-encoded UK postcode or part of an address that you wish to look upnr1%201ne

Querystring parameters

formatSets the format of the response, xml or json (default unless "application/xml" header is detected)format=json
identifierSpecifies your own meaningful identifier for the request such as "websiteA" or "client123"; you can view usage for each identifier on the Identifier Usage page, which may be helpful when using your API key across multiple websites, apps or clientsidentifier=websiteA
linesSets the number of address lines (1-9) to include in the response so you can mirror the layout of your existing address form; use include and exclude below to further customise the address lineslines=3
includeSpecifies the extra address fields to include within the address lines using a comma-delimited list, supported values: county, posttown, postcodeinclude=county,posttown,postcode
excludeSpecifies the address fields to exclude within the address lines using a comma-delimited list, supported values: pobox, organisation, departmentname, buildingname, subbuildingname, number, premise, dependentstreet, street, doubledependentlocality, dependentlocalityexclude=organisation
addtagsSpecifies the extra address fields to include within the response using a comma-delimited list, supported values: latitude, longitude, udprn, deliverypointsuffix, usercategory... see additional response fields below for the full listaddtags=latitude,longitude
postcodeonlyLimits the request to a postcode-only search rather than matching the search term on other parts of an address, UK only, true or false (default)postcodeonly=true
callbackSpecifies the name of your JSONP callback functioncallback=jsoncallback
pageSpecifies the index of the page of results to return; the first page is returned by default and has an index of 0, the second page has an index of 1 and so on; see pagination for more infopage=1

Example request and response

Return Not Yet Built addresses with a postcode of NR1 1NE and include up to 3 address lines in the response:


		"addressline1": "101010 St. Faiths Lane",
		"summaryline": "101010 St. Faiths Lane, Norwich, Norfolk, NR1 1NE",
		"number": "101010",
		"premise": "101010",
		"street": "St. Faiths Lane",
		"posttown": "Norwich",
		"county": "Norfolk",
		"postcode": "NR1 1NE"

Response fields

summarylineA summary of the address, ideal for displaying in a drop-down listAllies Computing Ltd, 92 St. Faiths Lane, Norwich, Norfolk, NR1 1NE
addressline1The first address line, where the total number of address lines is defined by the lines querystring parameterAllies Computing Ltd
addressline2The second address line92 St. Faiths Lane
addressline3The third address line
addressline4The fourth address line
addressline5The fifth address line
addressline6The sixth address line
addressline7The seventh address line
addressline8The eighth address line
addressline9The ninth address line
poboxThe PO Box number
organisationThe organisation name at that addressAllies Computing Ltd
departmentnameThe department name
buildingnameThe building name
subbuildingnameThe sub-building name
numberThe house or flat number92
premiseThe premise, a combination of buildingname, subbuildingname and number92
dependentstreetThe dependent street
streetThe streetSt. Faiths Lane
doubledependentlocalityThe double dependent locality
dependentlocalityThe dependent locality
posttownThe post townNorwich
countyThe countyNorfolk
postcodeThe postcodeNR1 1NE
notyetbuiltA true or false indicating whether the address is from the Royal Mail Not Yet Built datasetfalse
aliasA true or false indicating whether the address is a Royal Mail Alias recordfalse
recodesA colon-separated list of the previous postcode, previous delivery point suffix and the date it changed (YYYYMM format)CM7 8PX:1A:200112
morevaluesSet to true when there is another page of results beyond the current page; see pagination for more infotrue
nextpageThe index of the next page of results; see pagination for more info1
totalresultsThe total number of results found; see pagination for more info180

Additional response fields

Use the addtags querystring parameter to specify a comma-delimited list of fields that you wish to add to the response. For example, to add latitude, longitude and udprn:


Coordinate data
latitudeETRS89 latitude (ideal for use with mapping APIs)52.6299163702
longitudeETRS89 longitude (ideal for use with mapping APIs)1.3018030246
latitudeosgbOSGB36 latitude52.6294875459
longitudeosgbOSGB36 longitude1.3035999409
grideastingEasting OS Grid Reference (1m precision in units of 1m)623545
gridnorthingNorthing OS Grid Reference (1m precision in units of 1m)308689
Address fields
deliverypointsuffixDelivery Point Suffix3JS
uniquedeliverypointreferencenumberUnique Delivery Point Reference Number (UDPRN); there is no additional credit cost for including this field; you can also use addtags=udprn50959190
multipleoccupancycountMultiple Occupancy Count - count of the number of multiple occupancy addresses for the delivery point0
administrativecountyAdministrative County (top tier local government)Norfolk
postalcountyFormer Postal County
traditionalcountyTraditional CountyNorfolk
usercategoryUser Category ('R' for Residential, 'N' for Non-residential, 'L' for Large User)N
sortcodeSortcode for Royal Mail Mailsort35529
countrycodeCountry code within the United Kingdom064
countryCountry name within the United KingdomEngland
welsh_dependentstreetWelsh language alternative for dependent street field
welsh_streetWelsh language alternative for street field
welsh_doubledependentlocalityWelsh language alternative for double dependent locality field
welsh_dependentlocalityWelsh language alternative for dependent locality field
welsh_posttownWelsh language alternative for post town field
Special PAF keys
The uniquedeliverypointreferencenumber is populated across countries and is the recommended primary key. For Royal Mail PAF addresses only, the following keys can be used as a composite primary key in this order: addresskey,organisationkey,postcodetype.
addresskeyThe 8-digit PAF Address Key from Royal Mail (UK only)00001000
organisationkeyThe 8-digit PAF Organisation Key from Royal Mail (UK only, '0' for Residential Small Users and Large Users)00456120
postcodetypeThe PAF Postcode Type from Royal Mail (UK only, 'S' for Small Users, 'L' for Large Users)S
Census data
oa112011 Census Output AreaE00136551
lsoa112011 Census Lower Layer Super Output AreaE01033438
msoa112011 Census Middle Layer Super Output AreaE02006907
NHS data
commissioningregioncode_gssNHS Commissioning Region Code (ONS GSS)E40000007
commissioningregionnameNHS Commissioning Region NameNHS England East of England
areateamcode_nhsNHS Area Team Code (NHS)QMM
areateamcode_gssNHS Area Team Code (ONS GSS)E54000022
areateamnameNHS Area Team NameNHS Norfolk and Waveney Integrated Care Board
clinicalcommissioninggroupcode_nhsNHS Clinical Commissioning Group Code (NHS)26A
clinicalcommissioninggroupcode_gssNHS Clinical Commissioning Group Code (ONS GSS)E38000239
clinicalcommissioninggroupnameNHS Clinical Commissioning Group NameNHS Norfolk and Waveney ICB - 26A
Government data
localauthoritycodeLocal Authority CodeE07000148
localauthoritynameLocal Authority NameNorwich
electoralwardcodeElectoral Ward CodeE05012910
electoralwardnameElectoral Ward NameThorpe Hamlet
electoralcountycodeElectoral County CodeE10000020
electoralcountynameElectoral County NameNorfolk
parliamentaryconstituencycodeWestminster Parliamentary Constituency CodeE14000864
parliamentaryconstituencynameWestminster Parliamentary Constituency NameNorwich South
europeanelectoralregioncodeEuropean Electoral Region CodeE15000006
europeanelectoralregionnameEuropean Electoral Region NameEastern
nationalparkcodeNational Park CodeS21000003
nationalparknameNational Park NameThe Cairngorms National Park


When a request returns many addresses, Postcoder may paginate the response across multiple pages. The first page is returned by default and has an index of 0.

If another page is available, the last address on the current page will include two extra fields: morevalues (indicates another page is available when "true") and nextpage (provides the index of the next page).

        // Last address on current page
        "posttown": "Norwich",
        "county": "Norfolk",
        "postcode": "NR1 1NE",
        "morevalues": "true",
        "nextpage": "1",
        "totalresults": "180"

You can retrieve the next page by setting the page querystring parameter to the index of the next page. In the scenario above, you could do this by adding ?page=1 to your request.

Postcoder will truncate large responses to 60 pages; this limit may change from time to time.

Integration advice

  • URL encode all special characters (including /) in your request parameters with %xx encoding
  • Verify your request was successful by checking for an HTTP status code of 200; see all HTTP status codes with descriptions
  • When using your API key across multiple websites, apps or clients, set the identifier querystring parameter to a meaningful value such as "websiteA" or "client123"; you'll then be able to view these identifiers and the number of requests made by each one on the Identifier Usage page
  • Treat all response fields as optional
  • Use these fields on your UK address form: addressline1, addressline2, addressline3, posttown, postcode (county is no longer required in UK addresses)

Credit cost

Each request costs the following number of credits:

Standard requestEnhanced request using addtags
1.8 credits2.2 credits

Buy a credit pack or set up a monthly plan to use with all Postcoder endpoints.