Address Lookup & Validation
Capture accurate addresses the moment a customer starts typing. Our type-ahead lookup and validation API is powered by Royal Mail PAF and authoritative international datasets — so every address you collect is real, deliverable and standardised before it ever reaches your database.
What is Address Lookup & Validation?
Address lookup turns a few keystrokes or a postcode into a complete, verified address. As a user types, our type-ahead engine suggests matching premises in real time, drawing on Royal Mail's Postcode Address File (PAF) and Postcode Address Base (PAB) for the UK and rooftop-accurate datasets for 245 countries worldwide.
Behind the lookup sits a full validation and enrichment layer: postcode lookup, geocoding to precise lat/long coordinates, address standardisation to a consistent format, and deduplication to remove the near-duplicate records that quietly corrupt every CRM. The result is data that is correct at the point of capture — and stays correct over time.
Best for:
- Checkout and signup forms — eliminate typos that cause failed deliveries
- KYC and onboarding flows that require verified address evidence
- Cleansing and deduplicating CRM or customer databases at scale
- Reducing card fraud through Address Verification Service (AVS) checks
- Logistics and delivery routing with precise geocoded coordinates
- Faster form completion and measurably higher conversion rates
Why teams build on Welcome Address Lookup.
Fewer Failed Deliveries
Validating against Royal Mail PAF at the point of capture removes mistyped and undeliverable addresses, cutting the redelivery fees, returns and support tickets that come with them.
Higher Form Conversion
Type-ahead capture lets customers select a full address in a few keystrokes instead of filling five fields, reducing friction and abandonment on mobile checkouts and signups.
Cleaner Data
Standardisation and deduplication produce a single, consistently formatted address record per customer — improving analytics, mailings and the accuracy of every downstream system.
Global Coverage
One API spans 245 countries with rooftop-level accuracy, so the same integration validates a London postcode and a São Paulo street address with equal confidence.
Powered by authoritative address data
GDPR-aligned, UK-licensed data sources
Specialist Tip
Lead with the postcode field, not the street. Type-ahead address capture typically cuts checkout form time by around 30% and slashes failed-delivery costs, because most customers know their postcode by heart — let them select the rest from a verified list rather than typing it. It is one of the highest-ROI conversion changes you can make to a UK form.
More ways to verify and enrich your data.
Ready to capture clean, deliverable addresses?
Drop type-ahead address lookup into your forms today. Our team will help you get set up — transparent usage-based pricing as you scale, no setup fees.