Playlists and search on Youtube
Program provides two ways to search on Youtube and to load Youtube playlists and channels. First one (let's call it "WEB") extracts all info from corresponding web pages. The second one (let's call it "API") uses Youtube Data API to get all info.
WEB way can break from time to time due to internal changes on the site. But unlike the API way it does not have usage limits. This is default way used in the program.
Until some program version the API way was the only way to search on Youtube and load playlists (background is in Retrospective below). Now it works only if you supply your own Youtube Data API key (how to get it is described below in topic Youtube Data API key). Unlike WEB way, the chance that it will break is very low but it implies usage limits (a "quota").
Which way to use is determined by existence of API key. If it is configured (via program options) then API way is used. Otherwise WEB way is used.
Next page of search results and playlists is always retrieved using the same method as the first page. If you switch to API way in between, WEB way for next pages will be used anyway. If you switch to WEB way in between, program will fail getting next page with an error saying that API key is not configured.
Below is comparison table of WEB and API ways. Each way has pros and cons, so it is actually not easy to say which one is better.
|Variety of search filters||Exclusive features: 4K, 360°, VR180, HDR||API does not provide a way to search for 4K, 360°, VR180, HDR|
|Search items per page||20||50|
|Search results completeness||No likes/dislikes||Complete|
|Upload date in search results||Relative, approximated (e.g. "5 years ago"), localized in program language||Absolute, exact (date+time), localized in system language|
|View count in search results||Approximated (e.g. "18M" for ~18 million), localized in program language||Exact number|
|Playlist items per page||100||50|
|Playlist items completeness||No upload date, likes/dislikes and view count||Complete|
|Possibility to break due to internal change on the site||Average||Low|
Youtube Data API used to be public and free. With complete switch to API v3 they made it not public but bound to Google account. Any account can create API key, but anyway this means you have to have an account and there is no anonymous access to API anymore (a key is required which uniquely identifies an account on behalf of which requests are made).
With API key they introduced a "quota" thing, aka daily limit for requests project can make using particular API key. Quota resets at midnight Pacific Time (PT). Once limit is reached, key becomes unusable until that time.
Initially new projects were getting huge quota number (50 million). With time Google lowered it drastically (details and time line are in this SO answer). Now it is 10K which is mostly enough for a single user, not for an app.
Quotas for existing projects were also reviewed. Throughout 2019, users with existing projects were receiving emails notifying that their quota was lowered to
(~1.5 * N) value, where
N is maximum quota usage for past 90 days. So if your key usage grows with time, you eventually will hit the limit. If usage drops with time, limit will be decreased again. If usage stays on the same level, then
it is already zero level you are ok for now.
Project can apply for quota increase. There is no definite public answer whether this free or not. But for sure this can end up with zeroed quota if project will be considered as not satisfying Youtube Data API terms of service.
Youtube Data API key
Any Google account can create Youtube Data API key. Use of API key belonging to some account does not mean you are "logged in" with this account. User authentication is completely separate thing. So the use of your own key does not mean program can access your Youtube account in any way (like get or modify Watch Later queue) and it does not mean program will be able to access videos which require user to be signed in on the site.
To obtain API key, follow instructions in this topic (steps 1-3). In step 2 (obtaining authorization credentials) follow instructions for API key creation. When selecting API key type, select Browser key type.
To enter API key in the program, go to menu
Tools Options Advanced net.yt_api_key.
As of Feb-2020 new projects get 10000 quota limit (reminder: it is per-day limit). Within this limit you can get for example 100 search pages or 1000 playlist pages. You can learn more about quota costs using Quota Calculator and related documentation.
Help Miscellaneous Playlists and search on Youtube