Address autocomplete — also called an address finder — is a form feature that suggests real, deliverable addresses as a user types, letting them select the correct one instead of typing it in full. In the UK the suggestions come from Royal Mail's Postcode Address File (PAF), which holds around 31 million addresses across roughly 1.8 million postcodes, so every selected address is real and correctly formatted.
How does address autocomplete work?
As the user types a postcode or the first few characters of an address, the field queries Royal Mail PAF in real time and shows matching addresses in a dropdown. Selecting one populates every field with a standardised, verified address — no manual typing required.
- User types a postcode or partial address
- Real PAF addresses appear in a live dropdown
- User taps the correct one
- All fields fill with a standardised, verified address
Autocomplete vs validation vs verification
| Term | When it helps | Result |
|---|---|---|
| Autocomplete | During entry | User picks a real address fast |
| Validation | On submit | Confirms correct format |
| Verification | On submit / batch | Confirms it exists & delivers |
Autocomplete effectively validates by construction — users can only choose genuine PAF addresses. For the underlying concepts, see what address validation means.
How do I add address autocomplete?
Drop it into any form with our address autocomplete API or a no-code plugin. Prefer a hosted widget? Our address finder works out of the box.
A modern, UK-first alternative
AutoPostcode is a developer-friendly, affordable alternative to Loqate, Fetchify and Ideal Postcodes — the same Royal Mail PAF data, a faster integration and clearer pricing.
Frequently asked questions
What is address autocomplete?
Address autocomplete (also called an address finder) suggests real, deliverable addresses as a user types, letting them pick the correct one instead of typing it in full. In the UK, suggestions come from Royal Mail's PAF dataset of around 31 million addresses across 1.8 million postcodes.
How does address autocomplete work?
As the user types a postcode or the first characters of an address, the field queries Royal Mail PAF in real time and returns matching addresses in a dropdown. Selecting one fills every field with a standardised, verified address.
What is the difference between address autocomplete and validation?
Autocomplete helps users pick a real address quickly during entry; validation confirms an address is real and correctly formatted. Autocomplete effectively validates by construction, because users can only select genuine PAF addresses.
Does address autocomplete reduce checkout abandonment?
Yes. Autocomplete cuts the number of keystrokes and form errors, which speeds checkout and reduces abandonment — a common cause of lost ecommerce revenue.
Does address autocomplete work on mobile?
Yes, and it matters most on mobile where typing is slow. A few taps select a full address, removing the biggest source of mobile form friction.
Where does the address data come from?
AutoPostcode's autocomplete is powered by Royal Mail PAF — the official, continuously updated record of every deliverable UK address — served over a fast REST API.
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