This is a plugin aimed mostly at researchers with growth data wanting to calculate centiles and SDS.
It will be published as an addin for google sheets.
Users will have to sign up at [https://dev.rcpch.ac.uk] to obtain an API key. This can be done in a few minutes and is free. The api key is then entered into the spreadsheet and this authenticates the user.
There is a limit to the number of daily requests on the free tier.