Postcodes.io is a free and open source project.
It enables users to query, reverse geocode and retrieve UK postcode and related data.
The ONSPD dataset is updated quarterly.
Data from Great Britain may be used freely subject to the Ordnance Survey (OS) OpenData licence.
Data from Norther Ireland (postcodes beginning with
BT) may be used under the terms of the ONSPD licence. Non-commercial use is free. Commercial use requires a licence from NI & Property Services.
More information on licensing can be accessed on the Office for National Statistics licensing page.