UK address data underpins ecommerce checkouts, CRMs, logistics and compliance. At its heart sits the Royal Mail Postcode Address File (PAF) — the authoritative record of every deliverable address in the United Kingdom. This guide explains the data, the rules around it, and how to use it well.
What you'll learn
- What the Postcode Address File is and what it contains
- How UK postcodes are structured and what each part means
- How PAF licensing works and how to stay compliant
- How to integrate authoritative address data via an API or plugin
Why authoritative address data matters
Free or scraped address lists go stale quickly and miss new-build properties. Using PAF-backed data means your customers can find their exact address, your deliveries reach the right door, and your records stay clean for analytics and compliance.
- Around 31 million UK addresses kept up to date by Royal Mail
- Roughly 1.8 million postcodes covering the whole UK
- Continuous updates as properties are built, merged or removed
Start with the fundamentals
New to UK addressing? Begin with what a UK postcode is and how postcodes work. Ready to build? Jump to our Postcode Lookup API.
Frequently asked questions
What is the Royal Mail PAF?
The Postcode Address File (PAF) is Royal Mail's official database of every UK address and postcode — around 31 million addresses and 1.8 million postcodes — used to verify, autocomplete and standardise addresses.
Who maintains UK postcode data?
Royal Mail maintains the Postcode Address File and updates it continuously as new addresses are built and others change.
How do I use PAF data legally?
PAF is licensed. Most businesses access it through a licensed provider like AutoPostcode, which handles the Royal Mail relationship and exposes the data via an API and plugins.
Ready to get started?
Add Royal Mail PAF-verified UK address lookup to your site in minutes — start free, no card required.