we are developing Alexa Skills and testing them using echo devices. We are in Italy and our Skills are using italian language.
As a further step, we'd like to integrate Alexa Voice Service (AVS) into our own mobile app (iOS and Android versions) in order to directly execute our skills without the need to install Alexa app.
Are there API to let us do such an integration? If yes, is it a free feature or do we need to pay extra fees? Do you have guides/manuals that could help us?