Most businesses expect that if a property exists, it should appear instantly in their address lookup. But in reality, the UK’s address landscape is constantly growing. Not all properties appear in the main Postcode Address File (PAF) straight away.
Royal Mail’s Not Yet Built (NYB) dataset contains over 700,000 UK addresses for properties that are in planning, under construction, or not yet ready to receive mail. These addresses do exist — they’ve been assigned postcodes and are part of real developments — they just haven’t reached the active delivery stage required for PAF inclusion.
Without NYB data, customers in new build areas are often blocked at checkout or during onboarding processes by the dreaded “address not found” error.
In this article, we explain what the NYB dataset includes, why it’s critical for UK organisations, and how Autoaddress supports it by default, at no additional cost.
What is Not Yet Built (NYB) address data?
Not Yet Built is a companion dataset to Royal Mail’s PAF. While PAF lists over 30 million active postal delivery points, NYB contains addresses that:
- Are planned but not yet constructed
- Are under construction
- Have an assigned postcode but aren’t receiving mail yet
- Use the same structure as PAF (making them easy to integrate)
Once a property becomes occupiable and Royal Mail can deliver to it, the NYB record is retired and the address moves into PAF.
Why Not Yet Built data matters for UK businesses
Every year, the UK adds roughly:
- 100,000 new residential properties
- 26,000 new postcodes
However, these new build homes and commercial units often remain missing from PAF for months.
If your address capture solution relies solely on PAF, this lag causes:
- Checkout failures
- Abandoned sign-ups
- Increased support workload
- Customer frustration and loss of trust
NYB data eliminates these issues by recognising new build addresses as soon as they are officially registered, not weeks after people move in.
With Not Yet Built data, you can:
Accept orders and registrations earlier
Customers can complete purchases even if they haven’t moved in yet.
Enable faster service activation
Broadband, utilities, and insurers can validate a property and set up services in advance.
Prevent “address not found” support tickets
Removing this friction lowers operational costs and improves customer satisfaction.
Improve fraud, risk and eligibility checks
Financial services benefit from reliably identifying properties in planned developments.
Enhance planning and analytics
Identify emerging areas, track property growth, and tailor marketing campaigns.
How the NYB dataset works
Royal Mail collects and maintains NYB data based on submissions from:
- Local authorities
- Developers and builders
- Planning departments
The dataset includes standard PAF-style fields:
- Organisation
- Sub-building
- Building name/number
- Thoroughfare
- Locality
- Town
- Postcode
Key characteristics:
- UK-wide coverage
- Over 700,000 active NYB records
- Monthly or quarterly updates
- Seamless transition into PAF when properties become active
- Compatible with UPRN and geocoding sources (via complementary datasets such as AddressBase)
NYB is specifically designed to fill the gap between planning approval and postal activation — a period where traditional PAF-only solutions fall short.
Use cases for Not Yet Built address data
eCommerce & delivery
Ensure that customers in brand-new estates can place orders immediately, not weeks after move-in day.
Utilities & telecoms
Validate new build properties so installations, meter setups, and activation dates align with customer handovers.
Financial services & insurance
Perform KYC, AML, underwriting, and property validation on legitimate addresses that don’t yet exist in PAF.
Public sector & housing
Maintain accurate records, support service allocation, and track developments across local authority areas.
Not Yet Built vs PAF vs multiple residences
These datasets complement each other. Together, they form a complete picture of the UK’s address lifecycle, from planning, to construction, to occupation, to multi-tenant structures.
PAF
Contains all active Royal Mail delivery points, i.e. properties that can currently receive mail.
Multiple Residences (MR)
Adds units within multi-occupancy buildings such as subdivided houses or student accommodation.
Not Yet Built (NYB)
Captures future properties, i.e. those that exist on planning and construction records but are not yet active delivery points.
How Autoaddress supports Not Yet Built data
At Autoaddress, we believe that address capture should “just work” — even for properties that aren’t officially live yet.
That’s why Not Yet Built data is included in Autoaddress by default, at no additional cost.
No new licence, no configuration, no API changes.
You benefit immediately from:
- Full coverage of 700,000+ NYB properties
- Automatic updates as Royal Mail adds new records
- Smooth onboarding for customers in new developments
- No more failed lookups or manual address entry for new builds
A consistent experience across PAF, MR, and NYB addresses
Every time Royal Mail updates NYB data, you see those addresses instantly in your Autoaddress integration.
Frequently Asked Questions
Because some providers rely solely on PAF. New build properties typically appear first in the Not Yet Built dataset, which contains over 700,000 addresses not yet included in PAF.
It may take weeks after construction is complete and the property becomes ready for mail delivery. Only then does the address transition from NYB into PAF.
Approximately 100,000 new residential properties and tens of thousands of new postcodes are added annually — and many of these appear first in the NYB file.
Yes. Autoaddress includes NYB automatically alongside PAF and Multiple Residence. There’s no extra cost and no setup required.
PAF lists active delivery points.
NYB lists future delivery points that exist but are not yet ready for mail.
