# AddressBase Technical Specification

AddressBase provides an address product containing both residential and commercial addresses where a Local Authority address has been matched to a Royal Mail PAF address. This allows users to link additional information about a property to a single address. The product also provides enhancements to the Royal Mail PAF data by assigning an X and Y coordinate on British National Grid and an ETRS89 projection, as well as a primary level classification, and a representative point code describing the positional quality.

This technical specification includes the following sections:

* [Data formats](https://docs.os.uk/os-downloads/products/addresses-and-names-portfolio/addressbase/addressbase-technical-specification/data-formats)
* [Supply and update](https://docs.os.uk/os-downloads/products/addresses-and-names-portfolio/addressbase/addressbase-technical-specification/supply-and-update)
* [AddressBase Premium structure](https://docs.os.uk/os-downloads/products/addresses-and-names-portfolio/addressbase-premium/addressbase-premium-technical-specification/addressbase-premium-structure)
* [Feature types](https://docs.os.uk/os-downloads/products/addresses-and-names-portfolio/addressbase/addressbase-technical-specification/feature-types)
* [Code list and enumerations](https://docs.os.uk/os-downloads/products/addresses-and-names-portfolio/addressbase/addressbase-technical-specification/code-list-and-enumerations)
* [CSV to GML mapping](https://docs.os.uk/os-downloads/products/addresses-and-names-portfolio/addressbase/addressbase-technical-specification/csv-to-gml-mapping)
* [Example records](https://docs.os.uk/os-downloads/products/addresses-and-names-portfolio/addressbase/addressbase-technical-specification/example-records)

## AddressBase fundamentals 

Additional documentation covering the complete family of AddressBase products is available in the AddressBase Fundamentals pages. These covers key elements of design for AddressBase products, including:

* [Future and past publication dates](https://docs.os.uk/os-downloads/products/addresses-and-names-portfolio/addressbase-fundamentals/future-and-past-publication-dates)
* [Unique Property Reference Number (UPRN)](https://docs.os.uk/os-downloads/products/addresses-and-names-portfolio/addressbase-fundamentals/unique-property-reference-number-uprn)
* [Coordinate reference systems](https://docs.os.uk/os-downloads/products/addresses-and-names-portfolio/addressbase-fundamentals/coordinate-reference-systems)
* [Classification scheme](https://docs.os.uk/os-downloads/products/addresses-and-names-portfolio/addressbase-fundamentals/classification-scheme)
* [Data sources](https://docs.os.uk/os-downloads/products/addresses-and-names-portfolio/addressbase-fundamentals/data-sources)
* [Street names and numbering](https://docs.os.uk/os-downloads/products/addresses-and-names-portfolio/addressbase-fundamentals/street-names-and-numbering)
* [Currency completeness and precision](https://docs.os.uk/os-downloads/products/addresses-and-names-portfolio/addressbase-core/addressbase-core-overview/currency-completeness-and-precision)
* [Product supply](https://docs.os.uk/os-downloads/products/addresses-and-names-portfolio/addressbase-fundamentals/product-supply)
* [AddressBase local custodian codes](https://docs.os.uk/os-downloads/products/addresses-and-names-portfolio/addressbase-fundamentals/addressbase-local-custodian-codes)
* [AddressBase Islands local custodian codes](https://docs.os.uk/os-downloads/products/addresses-and-names-portfolio/addressbase-fundamentals/addressbase-islands-local-custodian-codes)