Template code
KakaoTalk requirements state that, the template code to used for sending AlimTalk messages must be no more than 20 characters in length - this includes english letters, numbers, "-", "_", BUT most importantly, no spaces are permitted between the characters.
For example:
Template name
AlimTalk template names can be up to 150 characters in length. For example:
This is first delivery message to the customer sent after order is placed.
You can learn more about working with templates on the Sinch Developer Documentation site. There, you'll find comprehensive documentation that illustrates how Sinch supports KakaoTalk through the Conversation API.