# 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](https://docs.os.uk/os-apis/accessing-os-apis/os-places-api) 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](https://docs.os.uk/os-apis/core-concepts/authentication "mention")
* [error-codes](https://docs.os.uk/os-apis/core-concepts/error-codes "mention")
* [rate-limiting-policy](https://docs.os.uk/os-apis/core-concepts/rate-limiting-policy "mention")

## 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="technical-specification/find">find</a></td></tr><tr><td><strong>Postcode</strong></td><td>Return matched addresses based on a property's postcode.</td><td><a href="technical-specification/postcode">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="technical-specification/uprn">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="technical-specification/nearest">nearest</a></td></tr><tr><td><strong>BBOX</strong></td><td>Return matched addresses within a bounding box.</td><td><a href="technical-specification/bbox">bbox</a></td></tr><tr><td><strong>Radius</strong></td><td>Return addresses that intersect a radius.</td><td><a href="technical-specification/radius">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="technical-specification/polygon">polygon</a></td></tr></tbody></table>

[^1]: Unique Property Reference Number


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