> For the complete documentation index, see [llms.txt](https://docs.os.uk/os-apis/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-apis/accessing-os-apis/os-places-api/technical-specification.md).

# Technical specification

This technical specification explains the content of the OS Places API and the methods that you can use to call it.

{% hint style="info" %}
If you are not familiar with the OS Places API, please read the [overview documentation](/os-apis/accessing-os-apis/os-places-api.md) before proceeding.
{% endhint %}

## Core concepts

This specification does not cover core concepts that apply to all Ordnance Survey APIs.

Please read the following pages to learn more about OS API core concepts:

* [Authentication](/os-apis/core-concepts/authentication.md)
* [Error codes](/os-apis/core-concepts/error-codes.md)
* [Rate-limiting policy](/os-apis/core-concepts/rate-limiting-policy.md)

## API reference

OS Places API has seven types of requests, that fall into two categories:

#### Capture and verification

<table data-view="cards"><thead><tr><th></th><th></th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td><strong>Find</strong></td><td>Return matched addresses based on a free text search.</td><td><a href="/os-apis/accessing-os-apis/os-places-api/technical-specification/find.md">Find</a></td></tr><tr><td><strong>Postcode</strong></td><td>Return matched addresses based on a property's postcode.</td><td><a href="/os-apis/accessing-os-apis/os-places-api/technical-specification/postcode.md">Postcode</a></td></tr><tr><td><strong>UPRN</strong></td><td>Return matched addresses based on a <a data-footnote-ref href="#user-content-fn-1">UPRN</a>.</td><td><a href="/os-apis/accessing-os-apis/os-places-api/technical-specification/uprn.md">UPRN</a></td></tr></tbody></table>

#### GeoSearch

<table data-view="cards"><thead><tr><th></th><th></th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td><strong>Nearest</strong></td><td>Return the closest addresses to a pair of coordinates (X and Y).</td><td><a href="/os-apis/accessing-os-apis/os-places-api/technical-specification/nearest.md">Nearest</a></td></tr><tr><td><strong>BBOX</strong></td><td>Return matched addresses within a bounding box.</td><td><a href="/os-apis/accessing-os-apis/os-places-api/technical-specification/bbox.md">BBOX</a></td></tr><tr><td><strong>Radius</strong></td><td>Return addresses that intersect a radius.</td><td><a href="/os-apis/accessing-os-apis/os-places-api/technical-specification/radius.md">Radius</a></td></tr><tr><td><strong>Polygon</strong></td><td>Return matched addresses within a GeoJSON polygon or multi-polygon object.</td><td><a href="/os-apis/accessing-os-apis/os-places-api/technical-specification/polygon.md">Polygon</a></td></tr></tbody></table>

[^1]: Unique Property Reference Number


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