iSpeech is an online speech platform that offers a text-to-speech API among its offerings. Because it is online, iSpeech can be used on any operating system. iSpeech requires users to purchase an API key by visiting the iSpeech website and then entering that API key into AwesomeTTS.
iSpeech supports many different voice options, including multiple dialects and speakers of popular languages. Additionally, AwesomeTTS makes available the speed and pitch options available from the API.