YouTube API 3 channels by username and id inconsistant - youtube

Question

Why is it when I search for a channel by ID https://www.googleapis.com/youtube/v3/channels?part=contentDetails&id=UU-tdS40X5ld-a4KfarLJuDw&key=[YOUR_API_KEY] I get no items returned.
But when I search by userName, it returns the channel ID that I just searched for https://www.googleapis.com/youtube/v3/channels?part=contentDetails&forUsername=washingtonstateuniv&key=[YOUR_API_KEY]

Answer 1

when I search for a channel by ID .. I get no items returned.
Give the Try-it section for channels.list a try. I'm able to fetch JSON response by using these parameters:
part->contentDetails
id-> yourchannel ID
Authorize and Execute
The response it returned is not empty at all.
{
"kind": "youtube#channelListResponse",
"etag": "\"I_8xdZu766_FSaexEaDXTIfEWc0/FiuYcDu7WFmoFVcLDRvENYGl_tQ\"",
"pageInfo": {
"totalResults": 1,
"resultsPerPage": 1
},
"items": [
{
"kind": "youtube#channel",
"etag": "\"I_8xdZu766_FSaexEaDXTIfEWc0/QjMybH99xT3x-znrh2Yerx_0DWk\"",
"id": "{my channel id}",
"snippet": {
"title": "{my channel name}",
"description": "",
"publishedAt": "2011-10-10T15:30:40.000Z",
"thumbnails": {
"default": {
"url": "https://yt3.ggpht.com/-EN5H1HDHqIU/ABCDEFGHIJK/ABCDEFGHIJK/l2gqeYg94P8/s88-c-k-no-mo-rj-c0xffffff/photo.jpg"
},
"medium": {
"url": "https://yt3.ggpht.com/-EN5H1HDHqIU/ABCDEFGHIJK/ABCDEFGHIJK/l2gqeYg94P8/s240-c-k-no-mo-rj-c0xffffff/photo.jpg"
},
"high": {
"url": "https://yt3.ggpht.com/-EN5H1HDHqIU/ABCDEFGHIJK/ABCDEFGHIJK/l2gqeYg94P8/s240-c-k-no-mo-rj-c0xffffff/photo.jpg"
}
},
"localized": {
"title": "{my channel name}",
"description": ""
}
}
}
]
}
That's a lot of results for me.
But when I search by userName, it returns the channel ID that I just
searched for.
In the channels.list try-it docs above, forUsername is defined as the forUsername parameter specifies a YouTube username, thereby requesting the channel associated with that username. So I think it's doing it's job.
Additional note on forUsername parameter is that's it's used to translate your arbitrary legacy YouTube username, that's the old Youtube accounts, into a channel ID using v3 of the API. More of that in Work with Channel IDs guide.

Answer 2

when I search by userName, it returns the channel ID that I just
searched for
You miss the important part to search by forUsername or channelID. That is snippet part, not contentDetails.
by forUsername :
https://www.googleapis.com/youtube/v3/channels?&part=snippet,id&forUsername=RealMiBs&title&key={YOUR_API_KEY}
by id channel:
https://www.googleapis.com/youtube/v3/channels?&part=snippet,id&id=UC_pwIXKXNm5KGhdEVzmY60A&title&key={YOUR_API_KEY}
That will exactly returned to like below:
{
"kind": "youtube#channelListResponse",
"etag": "\"uQc-MPTsstrHkQcRXL3IWLmeNsM/VnicD0AYsCI7KlKKcdsmdIlWUMs\"",
"pageInfo": {
"totalResults": 1,
"resultsPerPage": 1
},
"items": [
{
"kind": "youtube#channel",
"etag": "\"uQc-MPTsstrHkQcRXL3IWLmeNsM/Nl4tuuOFwuPOdHmP_Ky3vuIQ2Gg\"",
"id": "UC_pwIXKXNm5KGhdEVzmY60A",
"snippet": {
"title": "CJENMMUSIC Official", <== Channel Name
"description": "Asia's No.1 Entertainment & Media Company", <== Channel Desctiption
"customUrl": "cjenmmusic", <=== Channel URL who has been qualified - to and for - claimed it
"publishedAt": "2011-03-25T04:48:40.000Z",
"thumbnails": {
"default": {
"url": "https://yt3.ggpht.com/-QMkGdFbhrOc/AAAAAAAAAAI/AAAAAAAAAAA/6boUKax-3EA/s88-c-k-no-mo-rj-c0xffffff/photo.jpg"
},
"medium": {
"url": "https://yt3.ggpht.com/-QMkGdFbhrOc/AAAAAAAAAAI/AAAAAAAAAAA/6boUKax-3EA/s240-c-k-no-mo-rj-c0xffffff/photo.jpg"
},
"high": {
"url": "https://yt3.ggpht.com/-QMkGdFbhrOc/AAAAAAAAAAI/AAAAAAAAAAA/6boUKax-3EA/s240-c-k-no-mo-rj-c0xffffff/photo.jpg"
}
},
"localized": {
"title": "CJENMMUSIC Official",
"description": "Asia's No.1 Entertainment & Media Company"
}
}
}
]
}
While if you just pointing to contentDetails, it will return to almost nothing:
{
"kind": "youtube#channelListResponse",
"etag": "\"uQc-MPTsstrHkQcRXL3IWLmeNsM/C7SnOhT2c-Fs2R9f6JlxlOPWc34\"",
"pageInfo": {
"totalResults": 1,
"resultsPerPage": 1
},
"items": [
{
"kind": "youtube#channel",
"etag": "\"uQc-MPTsstrHkQcRXL3IWLmeNsM/3RTKaEQC9GX8c58R2Bhd8G1y3zM\"",
"id": "UC_pwIXKXNm5KGhdEVzmY60A",
"contentDetails": { <============== detail contents
"relatedPlaylists": {
"uploads": "UU_pwIXKXNm5KGhdEVzmY60A",
"watchHistory": "HL",
"watchLater": "WL"
}
}
}
]
}