API Reference - uprns.io

Quick start

Look up a single property in one request. The example below resolves UPRN 100023336956 - a property on Downing Street, Westminster.

Base URLhttps://uprns.io

Building a client? Download the OpenAPI 3.1 schema - JSON or YAML - and generate types in your language of choice.

curl -H "Accept: application/json" \
     https://uprns.io/uprn/100023336956

const res = await fetch(
  "https://uprns.io/uprn/100023336956",
  { headers: { Accept: "application/json" } }
);
const record = await res.json();

import requests

r = requests.get(
    "https://uprns.io/uprn/100023336956",
    headers={"Accept": "application/json"},
)
record = r.json()

Response · 200 OK

{
  "uprn": "100023336956",
  "latitude": 51.503541,
  "longitude": -0.12767,
  "easting": 530047,
  "northing": 179951,
  "country": "England",
  "region": "London",
  "local_authority": "Westminster",
  "usrn": "8400071",
  "postcode": "SW1A 2AA"
}

Content negotiation

Every endpoint serves a human-readable HTML page to browsers and structured JSON to API clients from the same URL. Request JSON in either of two ways:

Method	How
Accept header	Accept: application/json - preferred for API clients.
Suffix	Append .json to the path, e.g. /uprn/100023336956.json - handy in a browser.

Rate limits & attribution

The API is rate-limited on a fair-use basis per IP. Typical interactive and batch use sits well within the limit; if you need the whole dataset, take the Parquet downloads instead of crawling endpoints.

The data is published under the Open Government Licence v3.0. You must acknowledge the source with the attribution statement: “Contains OS data © Crown copyright and database right 2026”, alongside ONS where postcode geography is used.

UPRN lookup

GET/uprn/:uprn

Returns the canonical record for a single Unique Property Reference Number - coordinates, full administrative geography and linked identifiers.

Path parameters

Name	Type	Description
uprn	string	Required. The UPRN, a 1-12 digit number. Leading zeros are not used.

Example

curl -H "Accept: application/json" https://uprns.io/uprn/100023336956
# -> 200 OK · UprnRecord

Returns a UprnRecord. Responds 404 with an Error body if the UPRN is unknown.

USRN lookup

GET/usrn/:usrn

Returns a street record and the UPRNs that sit on it. The linked UPRN list is paginated.

Path & query parameters

Name	Type	Description
usrn	string	Required. The Unique Street Reference Number.
page	integer	Optional. 1-based page of linked UPRNs. 50 per page.

Returns a UsrnRecord.

Postcode lookup

GET/postcode/:postcode

Returns the administrative geography for a postcode and the UPRNs whose nearest postcode it is. The UPRN list is paginated.

Path & query parameters

Name	Type	Description
postcode	string	Required. Case- and space-insensitive, e.g. sw1a2aa or SW1A 2AA.
page	integer	Optional. 1-based page of UPRNs. 50 per page.

Returns a PostcodeRecord.

UprnRecord

The full record for a UPRN. Human-readable names are returned alongside their ONS codes.

Field	Type	Description
uprn	string	Unique Property Reference Number, 1-12 digits. Persistent; never reused.
longitude	number \| null	ETRS89 longitude (OS Open UPRN).
latitude	number \| null	ETRS89 latitude (OS Open UPRN).
eastings	integer \| null	British National Grid easting (X), 1m resolution.
northings	integer \| null	British National Grid northing (Y), 1m resolution.
postcode	string \| null	Authoritative postcode for this UPRN (ONS UPRN Directory PCDS). Not a nearest-postcode approximation.
usrn	string \| null	USRN of the street this property sits on (OS Open Linked Identifiers, highest-confidence link).
toid	string \| null	TopographicArea TOID of the building footprint (OS Open Linked Identifiers).
road_link_toid	string \| null	RoadLink TOID of the nearest road segment (OS Open Linked Identifiers).
town	string \| null	Nearest populated place (OS Open Names) - the town or settlement this UPRN sits in.
best_fit	object	2021 Census geographies assigned by ONS's population-weighted best-fit methodology (National Statistics UPRN Lookup). Use these to match official ONS statistical outputs; they may differ from the authoritative point-in-polygon values near boundaries.
country	string \| null	UK constituent country (England, Scotland or Wales).
region	string \| null	Region (formerly Government Office Region). England only.
admin_county	string \| null	Administrative county. Null where the location falls outside a county-level authority.
admin_district	string \| null	Local authority district or unitary authority.
admin_ward	string \| null	Electoral / administrative ward.
parish	string \| null	Civil parish (England) or community (Wales).
ced	string \| null	County electoral division. England county areas only.
parliamentary_constituency	string \| null	UK Parliamentary constituency, July 2024 boundaries.
senedd_constituency	string \| null	Senedd Cymru (Welsh Parliament) constituency. Wales only, derived by spatial join.
senedd_constituency_no	integer \| null	Senedd Cymru constituency number (1-16). Wales only.
lsoa	string \| null	2021 Census LSOA name. In Scotland this is the Data Zone.
msoa	string \| null	2021 Census MSOA name. In Scotland this is the Intermediate Zone.
oa	string \| null	2021 Census Output Area code - the smallest census geography.
lsoa11	string \| null	2011 Census LSOA name.
msoa11	string \| null	2011 Census MSOA name.
workplace_zone	string \| null	2011 Census Workplace Zone code.
output_area_classification	string \| null	2021 ONS Output Area Classification (supergroup/group/subgroup) name.
rural_urban	string \| null	2021 Rural-Urban Classification.
built_up_area	string \| null	Built-up Area (2024).
ttwa	string \| null	Travel to Work Area - where most people both live and work.
national_park	string \| null	National Park this location falls within, if any.
index_of_multiple_deprivation	integer \| null	IMD rank for this location's LSOA. Lower ranks are more deprived. Scales differ per country and are not comparable across them.
sub_icb	string \| null	NHS Sub-ICB Location (formerly CCG). England only.
nhs_england_region	string \| null	NHS England Region. England only.
nhs_ha	string \| null	NHS health authority area (Health Board in Scotland/Wales).
primary_care_trust	string \| null	Primary care organisation. Naming differs across UK regions.
cancer_alliance	string \| null	Cancer Alliance. England only.
pfa	string \| null	Police force area.
lep1	string \| null	Primary Local Enterprise Partnership (historic; LEPs wound down 2024).
lep2	string \| null	Secondary Local Enterprise Partnership, where overlapping.
european_electoral_region	string \| null	European Electoral Region (historic).
nuts	string \| null	ITL code (formerly NUTS). Retained under the `nuts` name for backward compatibility.
codes	object	Official GSS codes for the geographies named on the parent object. Pseudo codes (e.g. E99999999) denote 'not applicable'.

UsrnRecord

Field	Type	Description
usrn	string	Unique Street Reference Number.
name	string \| null	Derived street name (OS Open Roads via OS Open Linked Identifiers). Null for unnamed streets.
street_type	string \| null	OS Open USRN street type: Designated Street Name, Numbered Street, Unnamed Street, or Privately Maintained Street.
road_classification	string \| null	OS Open Roads classification (A Road, B Road, Motorway, Unclassified, ...). Null where no road link is matched.
road_classification_number	string \| null	Road number such as A38 or M32, where classified.
local_authority	string \| null	Local authority district the street centroid falls within.
longitude	number \| null	WGS84 longitude of the street centroid.
latitude	number \| null	WGS84 latitude of the street centroid.
bbox	object \| null	WGS84 bounding box of the street geometry. Null where no geometry is stored.
uprn_count	integer	Number of UPRNs linked to this USRN.
uprns	string[]	UPRNs linked to this USRN (OS Open Linked Identifiers).

PostcodeRecord

Field	Type	Description
postcode	string	Postcode in canonical form.
longitude	number \| null	WGS84 longitude of the postcode centroid.
latitude	number \| null	WGS84 latitude of the postcode centroid.
eastings	integer \| null	British National Grid easting of the centroid.
northings	integer \| null	British National Grid northing of the centroid.
uprn_count	integer	Number of UPRNs assigned to this postcode.
uprns	string[]	UPRNs assigned to this postcode. Large postcodes are paginated by the page surface; the JSON record carries the full list.
country	string \| null	UK constituent country (England, Scotland or Wales).
region	string \| null	Region (formerly Government Office Region). England only.
admin_county	string \| null	Administrative county. Null where the location falls outside a county-level authority.
admin_district	string \| null	Local authority district or unitary authority.
admin_ward	string \| null	Electoral / administrative ward.
parish	string \| null	Civil parish (England) or community (Wales).
ced	string \| null	County electoral division. England county areas only.
parliamentary_constituency	string \| null	UK Parliamentary constituency, July 2024 boundaries.
senedd_constituency	string \| null	Senedd Cymru (Welsh Parliament) constituency. Wales only, derived by spatial join.
senedd_constituency_no	integer \| null	Senedd Cymru constituency number (1-16). Wales only.
lsoa	string \| null	2021 Census LSOA name. In Scotland this is the Data Zone.
msoa	string \| null	2021 Census MSOA name. In Scotland this is the Intermediate Zone.
oa	string \| null	2021 Census Output Area code - the smallest census geography.
lsoa11	string \| null	2011 Census LSOA name.
msoa11	string \| null	2011 Census MSOA name.
workplace_zone	string \| null	2011 Census Workplace Zone code.
output_area_classification	string \| null	2021 ONS Output Area Classification (supergroup/group/subgroup) name.
rural_urban	string \| null	2021 Rural-Urban Classification.
built_up_area	string \| null	Built-up Area (2024).
ttwa	string \| null	Travel to Work Area - where most people both live and work.
national_park	string \| null	National Park this location falls within, if any.
index_of_multiple_deprivation	integer \| null	IMD rank for this location's LSOA. Lower ranks are more deprived. Scales differ per country and are not comparable across them.
sub_icb	string \| null	NHS Sub-ICB Location (formerly CCG). England only.
nhs_england_region	string \| null	NHS England Region. England only.
nhs_ha	string \| null	NHS health authority area (Health Board in Scotland/Wales).
primary_care_trust	string \| null	Primary care organisation. Naming differs across UK regions.
cancer_alliance	string \| null	Cancer Alliance. England only.
pfa	string \| null	Police force area.
lep1	string \| null	Primary Local Enterprise Partnership (historic; LEPs wound down 2024).
lep2	string \| null	Secondary Local Enterprise Partnership, where overlapping.
european_electoral_region	string \| null	European Electoral Region (historic).
nuts	string \| null	ITL code (formerly NUTS). Retained under the `nuts` name for backward compatibility.
codes	object	Official GSS codes for the geographies named on the parent object. Pseudo codes (e.g. E99999999) denote 'not applicable'.

Error

All non-2xx responses share one shape.

Field	Type	Description
status	integer	HTTP status code.
error	string	Human-readable error message.

Response · 404 Not Found

{ "code": 404, "message": "No UPRN found for 999999999999" }

The uprns.io JSON API

Quick start

Content negotiation

Rate limits & attribution

UPRN lookup

Path parameters

USRN lookup

Path & query parameters

Postcode lookup

Path & query parameters

UprnRecord

UsrnRecord

PostcodeRecord

Error