The speaker can be left on all day for on-demand commands. Much like Apple’s Siri, which debuted in 2011 on its iPhone 4s device, Amazon Echo responds to a user’s voice and can act on requests and answer basic questions. Over time, it will adapt to a user’s speech patterns and preferences.

Users start the speaker up saying the wake up word “Alexa.” You can then issue a command of your choice, from “play music by Taylor Swift” to “add ice cream to my shopping list.” The device can also answer basic questions, such as “what day is Christmas?” or “how many ounces are in a pound?”

The speaker, which runs on Amazon Web Services, costs $199, or $99 for Amazon Prime members. Amazon Echo is available by invitation only in the coming weeks.

—Reuters contributed to this report.