Now
Example
https://api.blockdate.io/api/now.json

Encode
Example
https://api.blockdate.io/api/encode.json
Parameters
q - "YYYY-MM-DD HH24:MI:SS" or seconds since the UNIX epoch
tz - defaults to UTC

Decode
Example
https://api.blockdate.io/api/decode.json
Parameters
q - "BLOCK.MINUTE.SECOND"
tz - defaults to UTC

Google Sheet Encode
Here's an example of how to convert a date to a block height in google sheets.
=IMPORTDATA(CONCATENATE("https://api.blockdate.io/api/encode.json?field=block.height&q=",ENCODEURL(A1)))