> For the complete documentation index, see [llms.txt](https://docs.os.uk/os-downloads/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.os.uk/os-downloads/products/addresses-and-names-portfolio/addressbase-core/addressbase-core-technical-specification.md). # AddressBase Core Technical Specification This technical specification provides detailed technical information about AddressBase Core. It is targeted at technical users and software developers. AddressBase Core is a simple, accessible addressing data product giving Plug and Play access to Great Britain addressing data and additional attribution, without being time-consuming or complex. It provides live addressing records for England, Wales and Scotland based on Local Authority holdings of the Local Land and Property Gazetteer (LLPG). Other attribution includes secondary level classifications (detailing the use and type of an address) and a representative point code describing the positional quality of coordinates. This technical specification includes the following sections: * [Data formats](/os-downloads/products/addresses-and-names-portfolio/addressbase-core/addressbase-core-technical-specification/data-formats.md) * [Supply and update](/os-downloads/products/addresses-and-names-portfolio/addressbase-core/addressbase-core-technical-specification/supply-and-update.md) * [Attributes](/os-downloads/products/addresses-and-names-portfolio/addressbase-core/addressbase-core-technical-specification/attributes.md) * [Enumerations](/os-downloads/products/addresses-and-names-portfolio/addressbase-core/addressbase-core-technical-specification/enumerations.md) * [Example records](/os-downloads/products/addresses-and-names-portfolio/addressbase-core/addressbase-core-technical-specification/example-records.md) 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](/os-downloads/products/addresses-and-names-portfolio/addressbase-fundamentals/future-and-past-publication-dates.md) * [Unique Property Reference Number (UPRN)](/os-downloads/products/addresses-and-names-portfolio/addressbase-fundamentals/unique-property-reference-number-uprn.md) * [Coordinate reference systems](/os-downloads/products/addresses-and-names-portfolio/addressbase-fundamentals/coordinate-reference-systems.md) * [Classification scheme](/os-downloads/products/addresses-and-names-portfolio/addressbase-fundamentals/classification-scheme.md) * [Data sources](/os-downloads/products/addresses-and-names-portfolio/addressbase-fundamentals/data-sources.md) * [Street names and numbering](/os-downloads/products/addresses-and-names-portfolio/addressbase-fundamentals/street-names-and-numbering.md) * [Currency completeness and precision](/os-downloads/products/addresses-and-names-portfolio/addressbase-core/addressbase-core-overview/currency-completeness-and-precision.md) * [Product supply](/os-downloads/products/addresses-and-names-portfolio/addressbase-fundamentals/product-supply.md) * [AddressBase local custodian codes](/os-downloads/products/addresses-and-names-portfolio/addressbase-fundamentals/addressbase-local-custodian-codes.md) * [AddressBase Islands local custodian codes](/os-downloads/products/addresses-and-names-portfolio/addressbase-fundamentals/addressbase-islands-local-custodian-codes.md) --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation by asking a question. Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters: ``` GET https://docs.os.uk/os-downloads/products/addresses-and-names-portfolio/addressbase-core/addressbase-core-technical-specification.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.