The API can be called using the following syntax:

https://api.numbercheck.co.uk?api_key=[your api key]&tel=landline

For example:

https://api.numbercheck.co.uk?api_key=abc123abc123abc123&tel=01304383838

Your api key can be found in the 'Your Details' section of NumberCheck.

Landline should be the landline number to be checked in standard national format (e.g. 01442590800)