Generating and distributing a replacement playlist

An article of manufacture including a non-transitory computer-readable medium, having stored thereon program instructions that, upon execution by a server device, cause the server device to perform operations comprising:

• generating a first playlist for a client device, wherein the first playlist includes references to a first plurality of audio files in a first specified order, wherein playout of the first plurality of audio files has a first duration, wherein the client device and the server device are in communication with one another by way of a wide-area network, and wherein the client device includes an audio player application;
• transmitting, over the wide area network, the first playlist to the client device, wherein reception of the first playlist at the client device causes the audio player application to retrieve and play out at least some of the first plurality of audio files in the first specified order;
• while the client device is playing out a current audio file of the first plurality of audio files, receiving an instruction from the client device, wherein the instruction specifies that the client device has activated a sleep timer with a target duration;
• in response to receiving the instruction, generating a second playlist, wherein the second playlist includes references to a second plurality of audio files in a second specified order, wherein playout of the second plurality of audio files has a second duration that is:
• less than the first duration and within a threshold duration of the target duration;
• and
• transmitting, over the wide area network, the second playlist to the client device, wherein reception of the second playlist at the client device causes the audio player application to, after playout of the current audio file completes, stop playing out audio files from the first plurality of audio files and retrieve and play out the second plurality of audio files in the second specified order.