Thanks to the replies I finally got the streamer user_ID using this code
-H 'Accept: application/vnd.twitchtv.v5+json' \
-H 'Client-ID: uo6dggojyb8d6soh92zknwmi5ej1q2' \
-X GET https://api.twitch.tv/kraken/users?streamer_name
Ok, now I’m wondering which is the correct link to see when he goes on live? Cause I’ve searched into the link that BarryCarlyon has sent (the second one) and there are only ways to get lists of most watched streamer.
So now I’m searching for the request to see when he’s in live.