If you ever pay attention to your browser’s location bar, you may have noticed that, for a while now, the YouTube.com website has used playlist IDs that are prefixed with the characters “PL” when constructing the URLs for playlist pages. http://www.youtube.com/playlist?list=PL72CF07D200AA2AFA is one example of that. This practice of prepended playlist IDs previously didn’t extend over to the Data API—PL72CF07D200AA2AFA would not have been recognized as a valid playlist ID, but 72CF07D200AA2AFA would have.
Starting later today, Wednesday, August 22, the YouTube Data API will accept playlist IDs with the “PL” prefix whenever they’re used as metadata or in API request URLs. In most responses, the API will return playlist IDs with “PL” prefixes. The one exception is that for the next few days, searching for playlists will return playlist ids without the “PL” prefix. This will change on Tuesday, August 28, at which point the “PL” prefix will be included in playlist search results as well.
While we will continue to support using unprefixed playlist IDs as metadata or in API request URLs for the time being, at some point in the future we may require the “PL” prefix to be used whenever a playlist ID is provided. We’ll provide additional guidance if we do decide to stop supporting requests with unprefixed playlist IDs.
This change should be backwards compatible, but if you’re currently manipulating or comparing the playlist IDs that are returned via the API in any way, or making any assumptions about the length of the ID (which you shouldn't be), please make sure that your code will handle IDs that contain the “PL” prefix.
If you have any questions about this changes, please let us know in our developer forum.
Cheers,
—Jeffrey Posnick, YouTube API Team
