# Postcode Lookup and Address Validation Integration UK

Source: https://dijituldevelopments.co.uk/postcode-lookup-integration/
Updated: 2026-10-10

> dijitul developments adds UK postcode lookup and address autocomplete to checkouts, web forms, CRMs and bespoke software, using Royal Mail PAF-based providers. Customers type a postcode, pick their address, and you get clean, deliverable data. We built a free OpenCart postcode lookup module with CraftyClicks years ago, and every project is a fixed-price quote after a free chat.

## Problems this solves

- Deliveries fail because customers mistype their address
- Your CRM is full of postcodes in lower case, without spaces, or in the wrong field
- Checkout abandonment is higher on mobile where typing addresses is slow
- An old postcode plugin stopped working after a provider changed its API
- Field staff can't find properties because addresses don't match the map
- A lookup key was exposed in page code and someone used up your credits

## Key facts

- We built a free OpenCart postcode lookup module with CraftyClicks, which rebranded as Fetchify in July 2020
- Royal Mail's Postcode Address File (PAF) holds over 30 million UK delivery points, according to Ordnance Survey
- PAF-based providers include Fetchify, Ideal Postcodes, Loqate and getAddress.io, each with its own API and licensing
- Ordnance Survey AddressBase links addresses to a UPRN, useful for property, utilities and field services
- API keys stay on the server or are restricted by domain, never left open in front-end code
- Lookups are debounced and cached to keep usage costs down
- A manual entry fallback is always kept for new-build or missing addresses

## Why address capture matters

Every mistyped address costs something: a failed delivery, a returned parcel, an engineer at the wrong door, an invoice that never arrives. On mobile, typing a full address is also one of the slowest parts of any checkout. Postcode lookup fixes both. The customer types their postcode, chooses their address from a list, and your system receives it in a consistent, deliverable format.

We've been building this for a long time. Our free OpenCart postcode lookup module was built with CraftyClicks, which has since rebranded as Fetchify. The principles from that module still apply: fast lookups, correct field mapping, and a manual fallback that never blocks a sale.

## Where the address data comes from

Almost every UK lookup service is built on Royal Mail's **Postcode Address File (PAF)**. Ordnance Survey describes PAF as holding over 30 million UK postal addresses, each delivery point with its own Unique Delivery Point Reference Number (UDPRN). Providers licence PAF and add their own search, autocomplete and API on top.

For businesses that care about the property itself rather than just where post goes, Ordnance Survey's **AddressBase** products match addresses to a **Unique Property Reference Number (UPRN)** and coordinates, combining PAF with local authority gazetteer data. That's useful for utilities, housing, surveyors and [field service software](https://dijituldevelopments.co.uk/software-for-field-services/), where a job is tied to a building.

## Choosing a provider

The main UK options include Fetchify, Ideal Postcodes, Loqate and getAddress.io. They differ in pricing model (per lookup, per address selected or subscription), autocomplete quality, international coverage, whether they return UPRNs and coordinates, and how keys are secured. We don't take commissions, so we'll recommend based on your volumes and needs. If you already have an account, we'll integrate the one you have.

| Need | What to look for |

| Busy ecommerce checkout | Fast type-ahead autocomplete and a pricing model that suits high volume |
| B2B forms | Organisation names returned as a separate field |
| Property or field services | UPRN and coordinates in the response |
| International customers | Global address coverage beyond PAF |

## How we integrate it

- **Front end:** a postcode button or type-ahead field that fits your existing form and works on mobile and with a keyboard.
- **Key security:** calls go through a small server-side proxy, or the provider's domain-restricted key, so your credits can't be used by anyone else.
- **Cost control:** we debounce keystrokes, cache recent postcode results and stop lookups on obvious typos.
- **Field mapping:** organisation, address lines, post town, county and postcode mapped to the right fields, including for platforms with fixed address structures.
- **Fallback:** an "enter address manually" option with postcode format checks, for new builds or service outages.

We integrate into [OpenCart](https://dijituldevelopments.co.uk/opencart-development/), WooCommerce, Magento, Shopify checkout extensions where your plan allows, and bespoke web apps.

## Getting the form right

A lookup that's awkward to use can make things worse. We build address forms that work for everyone:

- **Accessibility:** type-ahead fields follow the ARIA combobox pattern so screen reader and keyboard users can choose an address, and errors are announced clearly.
- **Browser autofill:** fields keep the right `autocomplete` attributes (`postal-code`, `address-line1`, `address-level2`) so a browser's saved address still works alongside the lookup.
- **Mobile:** large tap targets, a sensible keyboard and results that don't jump around as they load.
- **Format checks:** postcodes are normalised to upper case with a single space before the inward code, and the format is checked before any paid lookup is made, with sensible handling of special cases such as BFPO addresses.
- **Editable results:** the chosen address fills normal fields the customer can still correct, for example to add a flat number.

## Cleaning the addresses you already have

A lookup only fixes new data. For existing customer, CRM or job records, we can run a bulk validation: match each address against PAF through the provider's API, standardise the format, flag anything that can't be matched for a person to check, and add UPRNs where available. It pairs well with a GDPR review of what you hold, a [data migration](https://dijituldevelopments.co.uk/data-migration/) or [CRM integration](https://dijituldevelopments.co.uk/crm-integration/). Quoted at a fixed price after a free chat: [get in touch](https://dijituldevelopments.co.uk/contact/).

## What we deliver

- Postcode lookup or type-ahead address autocomplete on checkout and forms
- Integration into OpenCart, WooCommerce, Magento, Shopify checkout extensions or bespoke apps
- Server-side proxy that hides your API key and applies rate limits
- Address fields mapped correctly: organisation, lines, town, county and postcode
- Bulk validation and cleaning of existing customer addresses
- UPRN and coordinates stored where the provider supports it
- Fallback to manual entry with basic postcode format validation

Technologies: Royal Mail PAF, Ordnance Survey AddressBase, Fetchify API, Ideal Postcodes API, Loqate API, PHP 8, JavaScript

## FAQs

### Which postcode lookup provider should we use?

It depends on your volume, the pricing model that suits you and what data you need back. Fetchify, Ideal Postcodes, Loqate and getAddress.io all use Royal Mail PAF data. dijitul doesn't take commissions, so we'll recommend the best fit or integrate the account you already have.

### Did dijitul build a postcode lookup for OpenCart?

Yes. dijitul built a free OpenCart postcode lookup module with CraftyClicks, the company now known as Fetchify. We still build and update postcode lookup integrations for OpenCart and other platforms.

### Can you add postcode lookup to Shopify checkout?

Shopify limits what can be changed in checkout depending on your plan. dijitul checks what checkout extensions your store can use and recommends the best option, which may be a provider's own Shopify app.

### How do you stop our postcode API key being misused?

We route lookups through a server-side proxy with rate limits, or use the provider's domain-restricted keys, so the key can't simply be copied from your page source and used elsewhere.

### What's the difference between a UDPRN and a UPRN?

A UDPRN identifies a Royal Mail delivery point in PAF. A UPRN, used in Ordnance Survey AddressBase, identifies a property or land parcel, including places that don't receive post. Property and utility businesses usually need the UPRN.

### Can you clean the addresses already in our database?

Yes. dijitul can validate existing addresses in bulk against PAF, standardise them, flag those that can't be matched and add UPRNs where your provider supports it, so your existing records are as clean as new ones.

## Pricing and contact

Every project gets a fixed-price quote after a free initial chat and a short scoping stage. You own the code and the data. Book a free chat: https://dijituldevelopments.co.uk/contact/ · 01623 650333 · info@dijitul.uk