API returns plain text. How to process it on server side?

Hi guys,

Anyone worked with APIs that return plain text?

Example: https://api.pwnedpasswords.com/range/0F3FB

How would you deal with it to perform some checks on server connect against a value sent in a form? I need to hash the input password, send the 5 first characters from the hash to the API via URL(0F3FB in the example), retrieve the contents, search in the response for the full hash password and return to the form info.

I am specially interested in the API part.

Thanks in advance.