Address Validation API for the UK — Royal Mail PAF® + UPRN | Acuris

🇬🇧 UNITED KINGDOM

Address validation API for the UK.

Validate and standardize UK addresses against the Royal Mail Postcode Address File (PAF®) — the country's authoritative address database — with the Ordnance Survey UPRN and coordinates returned. Acuris is a Royal Mail PAF Solutions Provider.

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✓ Licensed to Acuris GmbH as a Royal Mail PAF® Solutions Provider.
PAF®
Royal Mail authoritative file
UPRN
OS property reference, included
Delivery point
postcode-to-property accuracy
Lat / Lng
coordinates returned
One call in · a complete record out

What a UK validation returns

Send a partial or messy address; get back the deliverable PAF® address, its Unique Property Reference Number, and coordinates.

You send
10 downing st
london
↓ /validate
You get back
line_110 Downing Street
post_townLONDON
postcodeSW1A 2AA
uprnOS100023336956
lat / lng51.50335, -0.12768
deliverabletrue
av_statusVerified

// illustrative example. UPRN is the Ordnance Survey Unique Property Reference Number.

Coverage for the UK

Postal-grade, not mapping-grade

Validation

Authoritative PAF® deliverability

Every UK delivery point comes from the Royal Mail Postcode Address File — so you confirm an address is real and deliverable, correct it to the postal standard, and cut failed deliveries. This is the certification mapping APIs can't give you.

Identifier

The UPRN, included

Each validated property returns its Ordnance Survey Unique Property Reference Number — the stable UK-wide key for joining address data across systems, GIS and public records.

Geocoding

Coordinates for every address

Latitude/longitude returned alongside the validated address, for mapping, routing and territory analysis.

Your data

Keep your results

Store and reuse validated UK addresses for your own internal business use — subject to Royal Mail's PAF® terms (see the note below). Compare storage rights →

Honest note · UK PAF® data

Because UK results come from the Royal Mail PAF®, they carry Royal Mail's End User Terms: you may keep and use validated UK addresses for your own internal business, but if your right to use PAF® data ends (for example, your subscription terminates) you must stop using and delete PAF®-derived data, save one archival copy. We'd rather tell you that up front than bury it.

Reference · the UK address format

How UK addresses are structured

Building + street10 Downing Street — sub-building / building name or number, then the thoroughfare.
Post townLONDON — the Royal Mail post town, conventionally in capitals.
PostcodeSW1A 2AA — alphanumeric outward + inward code; the most reliable UK address key.
UPRNOrdnance Survey Unique Property Reference Number — a persistent numeric ID for the property, returned with every match.
Straight answers

UK address validation, answered

Is this based on the Royal Mail PAF®? +
Yes. UK validation is built on the Royal Mail Postcode Address File, the authoritative record of every UK delivery point. Acuris is licensed as a Royal Mail PAF® Solutions Provider, so you get postal-grade deliverability, not a mapping-grade approximation.
What is a UPRN, and do I get it? +
The Unique Property Reference Number — Ordnance Survey's stable, UK-wide identifier for a property. It's returned with every validated UK address, which makes joining and deduplicating address data across systems far more reliable than matching on text.
Can I store validated UK addresses? +
Yes, for your own internal business use — with one PAF® condition. You can keep and reuse validated UK results, but because they derive from Royal Mail PAF®, you must cease using and delete PAF®-derived data (bar one archival copy) if your right to use it ends. You may not resell or supply the data to third parties.
Do you also geocode UK addresses? +
Yes. Coordinates are returned alongside the validated PAF® address and UPRN, so one call covers validation, identification and geocoding.
🇬🇧 United Kingdom

PAF®-grade UK validation, with the UPRN and coordinates

Authoritative deliverability, the Ordnance Survey property reference, and geocoding — in one call. Free to start.

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UK address validation uses the Royal Mail Postcode Address File (PAF®), licensed to Acuris GmbH as a Royal Mail PAF® Solutions Provider; use is subject to the Royal Mail PAF® End User Terms. UPRN identifiers derive from Ordnance Survey OS Open UPRN under the Open Government Licence v3.0. PAF® is a registered trademark of Royal Mail Group Ltd; Ordnance Survey is a trademark of Ordnance Survey Ltd. Example responses are illustrative. Verified July 2026.