Currently, you can use Alexa to initiate streams from the following services:
Amazon Music
Audible
iHeartRadio
Pandora
TuneIn
While many of these services have crossover with Play-Fi, when a stream is started using Alexa Voice Services, it specifically comes from Amazon’s platform rather than from Play-Fi or any other protocol.
In addition to the above, more services are being added all the time. To manage and sign into these services with your Amazon account, use the Alexa app.